JP2011074245A - Adhesive composition for temporary fixation and working method of parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition for temporary fixation, wherein a workpiece is surely temporarily fixed and easily peeled off in a short time after working, by operation excellent in safety and preservation of environment, and to provide a working method of parts using the adhesive composition for temporary fixation. <P>SOLUTION: The adhesive composition for temporary fixation comprises: an adhesive; and a thermally expanded microcapsule having a thermal expansion initiation temperature 20°C higher than the melting temperature of the adhesive. Further, the working method of parts includes: a process of temporarily fixing the parts by using the composition; a process of subjecting the temporarily fixed parts to mechanical working; a process of heating a cured material of the composition to a temperature of the thermal expansion initiation temperature of the thermally expanded microcapsule or more and, thereby, releasing the parts subjected to the mechanical working from the temporary fixation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a temporary fixing adhesive composition and a method of processing a part using the same.

  Temporarily fixing the work object (work piece) to a support etc. with a temporary fixing adhesive, and after performing the required machining such as cutting, polishing, grinding, and drilling, the work object is peeled off. A machining method including a process is frequently used for processing a crystal resonator, an optical prism, an electronic component, a precision machine component, and the like. In this processing method, a hot melt adhesive such as pine crab or wax has been conventionally used as a temporary fixing adhesive, and after processing a workpiece to be processed, room temperature or heated methylene chloride, trichloroethylene, etc. The adhesive was melted and removed by immersing in a halogen-based organic solvent, and the processed part was peeled off from the support or the like.

  However, the halogen-based organic solvent used as a stripping solution for hot melt adhesives has a problem that it is harmful to human bodies and may contaminate the environment.

  Therefore, as a method for solving the above problem, there has been proposed a method of temporarily fixing with an acrylic adhesive and dipping in water, alcohol or the like to peel off (see, for example, Patent Documents 1 and 2).

  In Patent Document 1, temporary fixing is performed by using a temporary fixing adhesive containing a hydrophilic monomer or prepolymer as a component, and the workpiece is peeled off by being immersed in heated or boiled water for several hours after machining. A method is disclosed. Further, Patent Document 2 uses a temporary fixing adhesive composed of a hydrophilic vinyl monomer, polyalkylene oxide mono (meth) acrylate and a radical polymerization agent, and a peeling solution (water or A method is disclosed in which a workpiece is dipped in a mixture of water and a water-soluble organic solvent such as alcohol). Both methods use water or a mixture of water and water-soluble organic solvents such as alcohol in the stripping process, so they are safer and more environmentally safe than conventional methods using halogenated organic solvents. Excellent in properties.

  However, in these methods, the peeling liquid enters the inside from the outer peripheral portion of the temporary fixing adhesive, and the peeling of the parts proceeds by reducing the adhesive force of the temporary fixing adhesive. When the size of the object is increased and the adhesion area is increased, there is a problem that the time required for peeling becomes longer and workability is lowered.

Japanese Patent Laid-Open No. 10-245526 Japanese Patent Laid-Open No. 2001-226641

  The present invention was made to solve the above-described problems of the prior art, and can securely fix the workpiece to be processed, and after machining, the workpiece is removed from the adherend. A temporary fixing adhesive composition that can be easily and quickly peeled off by a simple, safe and environmentally friendly operation, and a part using such a temporary fixing adhesive composition It aims to provide a processing method.

  As a result of intensive studies in order to solve the above-mentioned problems, the present inventors, as a result, an adhesive composition for temporary fixing containing a thermally expandable microcapsule having a specific thermal expansion start temperature, and this temporary fixing It has been found that the above object can be achieved by a method for processing a part in which the adhesive composition is heated at a specific temperature, and the present invention has been completed.

  That is, the adhesive composition for temporary fixing according to one embodiment of the present invention contains an adhesive and a thermally expandable microcapsule having a thermal expansion start temperature that is 20 ° C. or more higher than the melting temperature of the adhesive. It is a feature.

  The part processing method according to another aspect of the present invention includes: (a) a step of temporarily fixing a part using the temporary fixing adhesive composition; and (b) machining the temporarily fixed part. And (c) heating the cured product of the temporary fixing adhesive composition to a temperature equal to or higher than the thermal expansion start temperature of the thermally expandable microcapsule to temporarily fix the machined part. And a step of removing from.

  According to the present invention, the object to be processed can be reliably temporarily fixed, and after machining, the object to be processed can be easily and easily operated by an operation excellent in safety and environmental conservation. In addition, a temporary fixing adhesive composition that can be removed from temporary fixing in a short time, and a method of processing a part using such a temporary fixing adhesive composition are provided.

  Embodiments of the present invention will be described below.

  As the adhesive used in the temporary fixing adhesive composition of the present invention, a rosin-based adhesive is suitable, for example, natural rosin such as gum rosin, tall oil rosin, and wood rosin; polymerization derived from this natural rosin. Stabilized rosin obtained by disproportionating or hydrogenating these natural rosin or polymerized rosin; adding unsaturated carboxylic acid such as (anhydrous) maleic acid or (meth) acrylic acid to natural rosin or polymerized rosin Unsaturated acid-modified rosin or the like obtained in this way is used. In addition, aqua wax 20/50/80 (main component: fatty acid glyceride), aqua wax 553/531/442 / SE (main component: polyethylene glycol, vinyl pyrrolidone copolymer) commercially available as hot-melt water-soluble solid waxes Products, glycerin polyether), PEG wax 20 (main component: polyethylene glycol) (trade name, manufactured by Nikka Seiko Co., Ltd.) and the like are also preferably used. These adhesives may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  The adhesive preferably has a melting temperature of 50 ° C. or higher and 120 ° C. or lower. If the melting temperature is less than 50 ° C., it tends to solidify during storage, and if it exceeds 120 ° C., the thermally expandable microcapsules may foam during the preparation of the adhesive composition.

  In addition, the thermally expandable microcapsule used in the temporary fixing adhesive composition of the present invention is expanded by heating, and when expanded, the cured product and adherend of the temporary fixing adhesive composition As a result, the adhesive force of the temporarily fixed adhesive composition to the adherend is reduced, so that the cured product can be easily peeled off from the adherend. This heat-expandable microcapsule is composed of a volatile liquid foaming agent and an outer shell made of a thermoplastic resin that contains the volatile liquid foaming agent.

  First, as the volatile liquid blowing agent, isobutane, isopentane, n-butane, n-pentane, neopentane, hexane or the like is used.

  As the volatile liquid foaming agent, those other than those described above can also be used. Examples of such volatile liquid blowing agents include freons such as dichlorofluoromethane, trichlorofluoromethane, dichlorofluoroethane, dichlorotrifluoroethane, trichlorotrifluoroethane, dichloropentafluoropropane, alternative freons, and petroleum ether. And chlorinated hydrocarbons such as methyl chloride, methylene chloride, dichloroethylene, trichloroethane, and trichloroethylene.

  Such a volatile liquid foaming agent is preferably contained in the thermally expandable microcapsule in an amount of 5% by mass to 30% by mass in order to obtain a sufficient expansion coefficient.

  Next, it is preferable that the thermoplastic resin constituting the outer shell is one that can be kept in a capsule state without being ruptured by thermal expansion. Examples of satisfying such conditions include, for example, a polymer of vinylidene chloride, acrylonitrile, methacrylonitrile, or methyl methacrylate, or a copolymer of two or more of these, for example, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride- Acrylonitrile-methyl methacrylate copolymer, acrylonitrile-methyl methacrylate copolymer, one or more of these and various monomers including vinyl halide, styrene monomer, vinyl acetate, butadiene, vinylpyridine, chloroprene A copolymer etc. are mentioned.

  These thermoplastic resins may be crosslinkable or crosslinkable with a crosslinking agent such as divinylbenzene, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, triacryl formal, triallyl isocyanate and the like.

  As the thermoplastic resin, those having an expansion start temperature of 80 ° C. or higher and a maximum expansion temperature of 150 ° C. or higher are preferably used. Among them, (meth) acrylonitrile homopolymer or (meth) acrylonitrile content is used. High copolymers are preferably used.

  In the present invention, a thermally expandable microcapsule having a thermal expansion start temperature that is 20 ° C. or higher, preferably 30 ° C. or higher, higher than the melting temperature of the adhesive described above. Here, the thermal expansion start temperature refers to a temperature at which the thermally expandable microcapsule starts to expand by heating. When the thermal expansion start temperature is less than 20 ° C. of the adhesive, the thermally expandable microcapsule expands when the workpiece is temporarily fixed, and the adhesive force may be reduced. However, if the thermal expansion start temperature is too high, the energy required for heating increases, and the workpiece may be damaged or the characteristics may be degraded by heating. Is preferably 150 ° C. or lower. When the above-described rosin-based adhesive is used, it is preferable to use a thermally expandable microcapsule having a thermal expansion start temperature of 70 ° C. or higher and 150 ° C. or lower.

  Moreover, it is preferable that the thermal expansion microcapsule has a maximum expansion temperature of 200 ° C. or lower. Here, the maximum expansion temperature refers to a temperature at which the expansion coefficient of the thermally expandable microcapsule is maximized. When the maximum expansion temperature exceeds 200 ° C., it is difficult to obtain a sufficient expansion amount. That is, in this case, in order to obtain a sufficient expansion amount, a large amount of heating energy is required, and the workpiece may be damaged or deteriorated in characteristics by heating. When the above-described rosin-based adhesive is used, it is preferable to use thermally expandable microcapsules having a maximum expansion temperature of 80 ° C. or higher and 200 ° C. or lower.

  The measurement of the thermal expansion start temperature and the maximum expansion temperature is performed by, for example, placing a thermally expandable microcapsule in a cylindrical aluminum container or the like and using a thermomechanical analyzer (TMA) (manufactured by Texas Instruments). Then, the temperature is increased in a state where a force is applied by a pressure terminal, and the amount of displacement in the vertical direction of the pressure terminal is measured. The temperature at which the displacement starts to be observed is the thermal expansion start temperature, and the temperature at which the displacement is maximized is the maximum expansion temperature.

  Further, the thermally expandable microcapsule (outer shell) has an average particle size of preferably 2 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less, in an unexpanded state, and 10 μm or more and 30 μm or less. It is even more preferable. If the average particle size of the thermally expandable microcapsules when not expanded is less than 2 μm, a sufficient expansion rate and expansion force cannot be obtained, and it may be difficult to peel off the workpiece. On the other hand, if the average particle size exceeds 50 μm, the thickness of the adhesive layer at the time of temporary fixing becomes too large, and thus production efficiency may be deteriorated. In addition, the average particle diameter of this thermally expansible microcapsule can be measured using laser diffraction scattering type particle size distribution measuring apparatus LA-920 (made by Horiba, Ltd.), for example.

  The thermally expandable microcapsule can be produced by a conventionally known method such as a coacervation method or an interfacial polymerization method.

  As the thermally expandable microcapsules, for example, commercially available products such as EXPANCEL manufactured by Nippon Philite Co., Ltd. and ADVANCEL manufactured by Sekisui Chemical Co., Ltd. (hereinafter, trade names) can be used.

  As an example of EXPANCEL, EXPANCEL 551 whose outer shell is made of a vinylidene chloride-acrylonitrile copolymer and encapsulates isobutane as a volatile liquid blowing agent (thermal expansion start temperature: about 100 ° C., maximum expansion temperature: about 147 ° C.) EXPANCEL 461 (thermal expansion start temperature: about 110 ° C., maximum expansion temperature: about 150 ° C.), outer shell made of acrylonitrile-methacrylonitrile copolymer, and EXPANCEL 091 (thermal expansion) containing isopentane as a volatile liquid blowing agent Start temperature: about 130 ° C., maximum expansion temperature: about 186 ° C.), EXPANCEL 092 (thermal expansion start temperature: about 130 ° C., maximum expansion temperature: about 191 ° C.), etc. Each of these expands up to about 60 times in volume.

  The content of the thermally expandable microcapsule in the temporary fixing adhesive composition is preferably 1% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 10% by mass or less. If the content of the heat-expandable microcapsule is less than 1% by mass, the expansion rate and expansion force of the adhesive layer at the time of heating (peeling) may be insufficient, and if it exceeds 20% by mass, it is temporarily fixed. Inadequate adhesive strength may result, and during machining such as cutting and polishing, the workpiece may fall off or be lost, and the processing durability may be reduced.

  The adhesive composition for temporary fixing of the present invention contains other components, for example, inorganic fillers, shape maintaining agents, etc., as necessary and within the limits of the present invention, in addition to the above-described components. Can be made.

  Examples of inorganic fillers include silica, alumina, talc, zirconium oxide, zinc oxide, barium oxide, magnesium oxide, beryllium oxide, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, and aluminum nitride powder. Can be mentioned. These can be used individually by 1 type or in mixture of 2 or more types. The inorganic filler preferably has an average particle size of 0.1 μm or more and 100 μm or less, and more preferably 1 μm or more and 30 μm or less, from the viewpoint of fluidity of the temporary fixing adhesive composition. In addition, the measurement of the average particle diameter of this inorganic filler can be measured, for example using a laser diffraction scattering type particle size distribution measuring apparatus.

  In preparing the temporary fixing adhesive composition of the present invention, conventionally known methods for preparing a resin composition, for example, the above-mentioned adhesive, thermally expandable microcapsules, and other blended as necessary These components can be uniformly mixed and kneaded by a mixer or the like. In addition, it is preferable to perform the process which mixes and knead | mixes each component uniformly at the temperature lower than the thermal expansion start temperature of the thermally expansible microcapsule to be used.

  Next, a part processing method using the temporary fixing adhesive composition of the present invention will be described below by taking a cutting process of a glass plate as an example. In addition, the material of the part temporarily fixed using the adhesive composition for temporary fixing of the present invention is not particularly limited, and besides glass, YAG, crystal, ruby, sapphire, quartz, alumina, zirconia, Examples thereof include ferrite, rare earth magnetic material, ferroelectric ceramic, silicon, titanium, titanium alloy, stainless steel, aluminum, iron, and brass.

  First, the temporary fixing adhesive composition is applied on a processing table heated above the melting temperature of the contained adhesive and below the thermal expansion start temperature of the thermally expandable microcapsules, and then preliminarily roughened such as lapping. A glass plate (part to be processed) having a required thickness after polishing is placed. The glass plate is preferably heated in advance. Then, the heating of the processing table is stopped, the glass plate is temporarily fixed on the processing table by gradually cooling to room temperature by natural heat dissipation and curing the applied adhesive composition for temporary fixing.

  Next, the required mechanical processing such as cutting, grinding, polishing, and drilling is performed on the glass plate temporarily fixed on the processing table. It should be noted that short-time joining such as soldering or brazing is also included in the machining of the present invention.

  Thereafter, the adhesive layer (a cured product of the temporary fixing adhesive composition) temporarily fixing the glass plate to the processing table is heated to a temperature not lower than the thermal expansion start temperature of the thermally expandable microcapsule, and the thermally expandable micro While expanding the capsule, the glass plate is peeled off from the processing table. When the thermally expandable microcapsule expands, the contact area between the adhesive layer and the glass plate decreases, so that the glass plate can be easily peeled from the processing table. In addition, since the adhesive is attracted to the surface of the expanded thermally expandable microcapsule, a glass plate having a clean surface free from adhesive residue can be obtained.

  In addition, after peeling a glass plate from a process table, you may further immerse, for example in about 80 degreeC hot water. Thereby, it can prevent more reliably that the residue of an adhesive agent remains on the glass plate surface.

  Moreover, it is preferable that the expansion rate of the adhesive layer as a whole is 2 times or more, preferably 2 times or more and 10 times or less due to the expansion of the thermally expandable microcapsules. If the expansion rate of the adhesive layer as a whole is less than 2 times, it may be difficult to peel the glass plate from the processed plate. Moreover, when it exceeds 10 times, there exists a possibility that a glass plate may be scattered at the time of peeling.

Here, the expansion coefficient of the adhesive layer as a whole is the density of a so-called unexpanded adhesive layer that has not thermally expanded the thermally expandable microcapsule ρ ₀ , and after the thermally expandable microcapsule is thermally expanded. when the density of the adhesive layer was [rho _1, the following formula:
Expansion coefficient of the entire adhesive layer = (ρ ₀ / ρ ₁ )
Is required. The expansion coefficient of the entire adhesive layer can be adjusted by, for example, the average particle size and content of the thermally expandable microcapsules and by heating conditions such as heating temperature and heating time.

  In such a part processing method, when a processed part is peeled off, it is not necessary to use a stripping solution, so that it is excellent in safety and environmental conservation. Further, since it is not necessary to wait for intrusion as in the case of using a stripping solution, the stripping time can be shortened and it can be sufficiently applied to a large-sized workpiece.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In the following description, “part” simply means “part by mass”.

Example 1
100 parts of hot-melt water-soluble solid wax (trade name Aqua Wax 80, manufactured by Nikka Seiko Co., Ltd.) and 5 parts of thermally expandable microcapsule (trade name: EXPANCEL 551 DU40, manufactured by Nippon Philite Co., Ltd .; average particle size: 15 μm) The mixture was mixed at 80 ° C. for 60 minutes to prepare a temporary fixing adhesive composition.

  Two slide glasses (length 76 mm, width 26 mm, thickness 1.3 mm) were prepared, left on a hot plate heated to 100 ° C. and heated, and then the adhesive resin composition on one slide glass An object was applied, and the other slide glass was overlaid thereon so as not to entrain air bubbles. These glass slides were cooled to room temperature and then cut into a width of 10 mm with a diamond cutter. During the cutting, the slide glass did not fall off or was broken, and it had good cutting durability.

  When the cut glass slide was left in an oven at 120 ° C. for 10 minutes, it could be separated into two glass slides.

(Example 2)
A temporary fixing adhesive composition was prepared in the same manner as in Example 1 except that the amount of the thermally expandable microcapsule (EXPANEL 551 DU40) was 1 part by mass. In addition, two slide glasses were temporarily fixed and cut using the obtained composition in the same manner as in Example 1. During the cutting, the slide glass did not fall off or was broken, and it had good cutting durability. Further, in the same manner as in Example 1, when the cut glass slide was left in an oven at 120 ° C. for 10 minutes, it could be separated into two glass slides.

(Example 3)
A temporary fixing adhesive composition was prepared in the same manner as in Example 1 except that the amount of the thermally expandable microcapsule (EXPANEL 551 DU40) was 20 parts by mass. In addition, two slide glasses were temporarily fixed and cut using the obtained composition in the same manner as in Example 1. During the cutting, the slide glass did not fall off or was broken, and it had good cutting durability. Further, in the same manner as in Example 1, when the cut glass slide was left in an oven at 120 ° C. for 10 minutes, it could be separated into two glass slides.

Example 4
Instead of the thermally expandable microcapsule (EXPANEL 551 DU40), the thermally expandable microcapsule (manufactured by Sekisui Chemical Co., Ltd., trade name ADVANCEL EMH201; average particle diameter 30 μm, thermal expansion start temperature: about 125 ° C., maximum expansion temperature : About 160 ° C.) A temporary fixing adhesive composition was prepared in the same manner as in Example 1. In addition, two slide glasses were temporarily fixed and cut using the obtained composition in the same manner as in Example 1. During the cutting, the slide glass did not fall off or was broken, and it had good cutting durability. Further, as in Example 1, when the cut glass slide was left in an oven at 150 ° C. for 10 minutes, it could be separated into two glass slides.

(Comparative example)
Two glass slides were temporarily fixed and cut using hot-melt water-soluble solid wax (Aqua Wax 80) in the same manner as in Example 1. During the cutting, the slide glass did not fall off or was broken, and it had good cutting durability. Thereafter, as in Example 1, when the cut glass slide was left in an oven at 120 ° C. for 10 minutes, it could be separated into two glass slides, but the release surface had an adhesive that could be visually confirmed. A residue was observed.

  Evaluation of adhesive strength and peelability of the temporary fixing adhesive composition or adhesive in each of the above Examples and Comparative Examples was carried out by the methods shown below. These evaluation results are shown in Table 1 together with the composition of the temporary fixing adhesive composition.

[Adhesive strength]
Prepare two stainless steel plates, apply a temporary fixing adhesive composition or adhesive on one stainless steel plate under the same conditions as described above, and dry the other stainless steel plate. Were overlapped without being caught and heated and pressurized under the conditions of 90 ° C. and 0.01 MPa. About this adhesive material, the tensile shear strength was measured using the tensile-compression test machine (Strograph R-1) by Toyo Seiki Seisakusho, and it was set as the adhesive force.

[Peelability]
After the two stainless steel plates were bonded in the same manner as in the above adhesive strength evaluation test, they were left in an oven at 120 ° C. for 10 minutes and separated into two glass slides. The separated (peeled) surface was visually and optically separated. It was observed with a microscope (100 times) to examine the presence or absence of adhesive residues. The evaluation criteria are as follows.
○: No residue that can be confirmed with an optical microscope Δ: There is a residue that can be confirmed with an optical microscope, but there is no residue that can be visually observed ×: There is a residue that can be visually observed

  As is apparent from Table 1, the temporary fixing adhesive composition according to the present invention containing thermally expandable microcapsules was excellent in adhesive strength and peelability after processing. On the other hand, in the comparative example using the conventional adhesive containing no thermally expandable microcapsules, the adhesive remained to be visually confirmed on the peeled surface, and an adhesive cleaning step was necessary. .

Claims (5)

  An adhesive composition for temporary fixing, comprising: an adhesive; and a thermally expandable microcapsule having a thermal expansion start temperature that is 20 ° C. or more higher than a melting temperature of the adhesive.   The adhesive composition for temporary fixing according to claim 1, wherein a thermal expansion start temperature of the thermally expandable microcapsule is 150 ° C or lower.   The adhesive composition for temporary fixing according to claim 1 or 2, comprising 1 to 20% by mass of the thermally expandable microcapsule.   The adhesive composition for temporary fixing according to any one of claims 1 to 3, wherein the adhesive is a rosin-based adhesive. (A) a step of temporarily fixing a component using the adhesive composition for temporary fixing according to any one of claims 1 to 4;
(B) machining the temporarily fixed part;
(C) heating the cured product of the temporary fixing adhesive composition to a temperature equal to or higher than the thermal expansion start temperature of the thermally expandable microcapsule, and removing the machined part from temporary fixing; A method for processing a part, comprising: