JP2006334745A - Adsorption pad for polishing and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorption pad for polishing capable of favorably adsorbing a polishing object in polishing and capable of easily connecting and disconnecting the polishing object after polishing and to provide its manufacturing method. <P>SOLUTION: The adsorption pad 11 for polishing has a film of a foam body higher in density than the inside on an adsorptive surface 21 by using one surface of a plate type body 19 made of a polyurethane foam body having a continuous pore structure as the adsorptive surface 21 of an LCD glass 14 being the polishing object and water repellency by a water repellency giving agent on a surface of the film. Additionally, the adsorption pad 11 for polishing is constituted so that the LCD glass 14 is adsorbed to a surface of the adsorption pad 11 for polishing in polishing and the LCD glass 14 is connected and disconnected to and from the adsorption pad 11 for polishing after polishing. It is favorable that a contact angle to the adsorptive surface 21 of the adsorption pad 11 for polishing is 95 to 115°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a polishing material used for holding a liquid crystal glass when polishing the liquid crystal glass used for a hard disk of a computer or a liquid crystal glass used for a television screen as a polishing object to increase the thickness accuracy. The present invention relates to a suction pad and a manufacturing method thereof.

In manufacturing this type of liquid crystal glass, a step of polishing the surface of the liquid crystal glass with a slurry in which cerium oxide as abrasive grains is dispersed in water is provided in order to increase the thickness accuracy. In such a polishing process, it is necessary to hold liquid crystal glass. For this purpose, a porous body such as a polyurethane foam or an isoprene rubber foam is used. As such a porous body, for example, a suction pad constituted by a porous soft resin sheet made of a foamed polyurethane resin is disclosed (for example, see Patent Document 1). The suction pad is attached to the surface of the pressure plate, and the glass substrate is sucked and held on the suction pad through water. On the other hand, at a position facing the glass substrate, a polishing cloth affixed on a polishing board rotated by a rotation drive shaft is disposed. Then, the surface of the glass substrate is polished with high precision by pressing the glass substrate against the polishing cloth and rotating the glass substrate while supplying slurry in which abrasive grains made of cerium oxide are dispersed in water.
JP 2004-276133 A (page 2, page 4 and page 5)

  However, since the suction pad described in Patent Document 1 is exposed to the polishing slurry during polishing of the glass substrate, the polishing slurry (water and abrasive grains dispersed in the water) is adsorbed from the surface of the suction pad. It penetrates into the pad. When the polishing slurry enters the suction pad, swelling occurs at the ingress portion of the polishing slurry according to the amount of entry, and minute irregularities are formed on the surface of the suction pad. On the other hand, the glass substrate is adsorbed on the flat surface of the adsorption pad through water. If the surface of the suction pad is not smooth and uneven portions are formed, the amount of water present thereon changes, the surface tension changes depending on the location, and the adsorptivity of the glass substrate to the suction pad changes. As a result, the polishing accuracy of the glass substrate may decrease, or the glass substrate may be displaced with respect to the suction pad. Further, when the glass substrate is peeled off from the suction pad for replacement after polishing the glass substrate, it is also required that the glass substrate can be easily peeled off from the suction pad.

  Accordingly, an object of the present invention is to provide a polishing suction pad that can satisfactorily adsorb an object to be polished at the time of polishing and that can be easily detached after polishing, and a method for manufacturing the same. There is.

  In order to achieve the above object, the polishing suction pad according to claim 1 is a polishing suction pad for absorbing a polishing object and polishing the polishing object with a polishing slurry in that state. In addition, one surface of a plate-like body made of polyurethane foam having an open cell structure is used as an adsorption surface for an object to be polished, and the adsorption surface has a foam film having a higher density than the inside, and the surface of the film. Has water repellency due to the water repellency imparting agent, and is characterized in that the object to be polished is adsorbed during polishing and the object to be polished is detached after polishing.

A polishing suction pad according to a second aspect of the invention is characterized in that, in the invention according to the first aspect, a contact angle on the suction surface is 95 to 115 °.
The method for producing a polishing suction pad according to claim 3 is a method for producing a polishing suction pad for adsorbing a polishing object and polishing the polishing object with a polishing slurry in that state. When a polyurethane foam raw material containing polyester polyols, polyisocyanates, foaming agent, catalyst and water repellency imparting agent is reacted, foamed and cured, it is maintained at a temperature lower than the temperature of the raw material before foaming or at the beginning of foaming. It is characterized by this.

  According to a fourth aspect of the present invention, there is provided the method for producing a polishing suction pad according to the third aspect, wherein the water repellency-imparting agent has a hydroxyl group and a hydrophobic group, and the hydroxyl group is converted to an isocyanate group of a polyisocyanate. It is characterized by being reacted and prepolymerized in advance.

  The manufacturing method of the polishing suction pad of the invention according to claim 5 is the invention according to claim 3 or claim 4, wherein the raw material is supplied onto the release film and reacted, foamed and cured, The release film is peeled off.

According to the present invention, the following effects can be exhibited.
In the polishing suction pad according to the first aspect of the present invention, one surface of the plate-like body made of polyurethane foam having an open cell structure is used as the suction surface of the object to be polished, and the suction surface has a density higher than the inside. Since it has a high foam film, entry of the polishing slurry into the suction pad is suppressed, and formation of minute irregularities on the surface of the suction pad is suppressed. Accordingly, the object to be polished can be adsorbed satisfactorily during polishing. Further, since the water repellency by the water repellency imparting agent is expressed on the surface of the film, water existing between the film surface of the suction pad and the object to be polished is repelled, and the object to be polished is adsorbed after polishing. It can be easily detached from the pad.

  In the polishing suction pad according to the second aspect of the invention, the contact angle on the suction surface is 95 to 115 ° and has a sufficient water repellency. Therefore, in addition to the effect of the invention according to the first aspect, the polishing target The desorption property of an object can be improved.

  In the method for producing a polishing suction pad according to claim 3, when the polyurethane foam raw material containing polyester polyols, polyisocyanates, foaming agent, catalyst and water repellency imparting agent is reacted, foamed and cured. In addition, it is maintained at a temperature lower than the temperature of the raw material before foaming or at the early stage of foaming. Therefore, a film can be formed on the surface by setting the temperature at the time of foaming low, and water repellency can be imparted to the surface by the water repellency imparting agent. As a result, a polishing suction pad that can exhibit the effect of the invention according to claim 1 can be easily manufactured.

  In the method for producing a polishing suction pad according to claim 4, the water repellency imparting agent has a hydroxyl group and a hydrophobic group, and the hydroxyl group is reacted with an isocyanate group of a polyisocyanate to be prepolymerized in advance. Is. For this reason, in addition to the effect of the invention according to claim 3, the water repellency-imparting agent can be reliably reacted with the polyisocyanates and incorporated into the polyurethane skeleton.

  In the manufacturing method of the suction pad for polishing of the invention according to claim 5, after the raw material is supplied onto the release film and reacted, foamed and cured, the release film is peeled off. In addition to the effects of the invention according to the third or fourth aspect, the film can be easily formed on the surface of the foam by the release film.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, a liquid crystal glass polishing apparatus will be described. As shown in FIG. 1, a polishing suction pad 11 is fixed on a surface plate 10 via an adhesive layer 12, and water is placed on the polishing suction pad 11. A liquid crystal glass 14 as an object to be polished is adsorbed via 13. The liquid crystal glass 14 is adsorbed on the polishing suction pad 11 by the surface tension of the water 13. The liquid crystal glass 14 is used for computer hard disks and screens, television screens, mobile phone screens, and the like. A disc-shaped rotating jig 16 supported by the rotating shaft 15 is disposed above the liquid crystal glass 14 so as to be rotatable at a predetermined rotational speed. A polishing pad 17 is fixed to the lower surface of the rotating jig 16 so as to be in sliding contact with the surface of the liquid crystal glass 14.

  Then, the polishing slurry 18 is supplied to the surface of the liquid crystal glass 14 while the rotating jig 16 is lowered and the polishing pad 17 is in contact with the surface of the liquid crystal glass 14, and the surface of the liquid crystal glass 14 is polished. ing. As the polishing slurry 18, for example, a slurry in which cerium oxide as polishing abrasive grains is dispersed in water is used. By this polishing, the thickness accuracy of the liquid crystal glass 14 is increased.

  The plate-like body 19 constituting the polishing suction pad 11 is formed of a polyurethane foam having an open cell structure. FIG. 2 is a diagram schematically showing a cross section of the polyurethane foam. As shown in FIG. 2, coatings (skin layers) 20a and 20b made of a cured product of the foam are formed on both surfaces of the foam. The thickness of the coatings 20a and 20b is about 2 to 50 μm. The surfaces of the coatings 20a and 20b serve as an adsorption surface 21 that adsorbs the liquid crystal glass 14.

  Further, a low density layer 22 is formed at the center of the foam, and high density layers 23a and 23b having a higher density than the low density layer 22 at the center are formed between the low density layer 22 and the coatings 20a and 20b. Is formed. That is, since the cells (bubbles) 24 formed by foaming are large at the center of the foam and small at the outside thereof, the density is small at the center and high at the outside. There are 4 to 5 cells 24 in the thickness direction of the polyurethane foam, and the cell 24 is an open-cell foam. In addition, the polyurethane foam shown in FIG. 2 represents the structure typically, and does not represent the open cell structure.

  Since it is preferable that the surface of the plate-like body 19 is smoother, the raw material of the polyurethane foam is supplied onto the release film having a smooth surface and foamed, and then the release film is peeled off. It is preferable to adopt a method in which the peeling surface is the adsorption surface 21. A specific method will be described. As shown in FIG. 3, resin films 27 and 28 made of polyethylene terephthalate (PET) as release films that have been subjected to a release treatment are provided on a pair of upper and lower delivery rollers 25 and 26, respectively. It is wound and sent out forward (rightward in the figure) so that both resin films 27 and 28 are overlapped. In this case, the delivery roller 26 at the lower position rotates to the right, and the delivery roller 25 at the upper position rotates to the left. As the resin films 27 and 28, an acrylic resin film, a polyamide resin film, or the like can be used.

  A raw material supply device 30 for discharging a polyurethane foam raw material (liquid) 31 from a supply port 29 opened downward is disposed below the feed roller 25 at the upper position. And the raw material 31 discharged from the supply port 29 of the raw material supply apparatus 30 is supplied on the resin film 28 sent out from the delivery roller 26 in the lower position and supported by the support base 32. A presser roller 33 is disposed at the front position of the raw material supply device 30, and the polyurethane foam raw material 31 is sandwiched between the resin films 27 and 28, and is pressed from the upper surfaces of both the resin films 27 and 28. The thickness between the resin films 27 and 28 is adjusted.

  A cooling box 34 is disposed in front of the presser roller 33, and the inside of the cooling box 34 is maintained at a temperature lower than the temperature of the polyurethane foam raw material 31 before foaming by the polyurethane foam raw material 31 or at the initial stage of foaming. Yes. And the membrane | film | coat 20 is formed in the surface of the polyurethane foam obtained. Specifically, the temperature of the raw material 31 is maintained near room temperature (15 to 30 ° C.), and the temperature of the cooling box 34 is set to a lower temperature, for example, 5 ° C. to less than 15 ° C. The thickness of the film 20 varies depending on manufacturing conditions, and the thickness of the coating 20 increases as the temperature of the cooling box 34 decreases and decreases as the temperature of the cooling box 34 increases, but is generally about 50 to 200 μm.

  A heating furnace 35 is provided in front of the cooling box 34, and heated air of about 70 to 100 ° C. is blown onto the foam to react and cure the polyurethane foam raw material 31. The polyurethane foam raw material 31 sandwiched between the resin films 27 and 28 is naturally foamed at a low temperature in the cooling box 34 after passing through the pressing roller 33, and then further reacted and cured (crosslinked) in the heating furnace 35. ) To produce polyurethane foam.

  Winding rollers 36 and 37 are arranged at the rear upper and lower positions of the heating furnace, and the resin films 27 and 28 on the surface of the polyurethane foam are peeled off and wound around the winding rollers 36 and 37, respectively. . In this way, the coatings 20a and 20b are formed on both surfaces of the polyurethane foam, and the surfaces are formed smoothly. The plate-like body 19 is obtained by this polyurethane foam or by slicing it. Since the surface of the plate-like body 19 becomes smooth, the liquid crystal glass 14 can be adsorbed and held in a stable state. Further, since a high-density film 20 is formed on the surface of the plate-like body 19 and the film 20 has a blocking property, the passage of water and abrasive grains on the surface of the plate-like body 19 is restricted. The

  The plate-like body 19 has an open-cell structure, that is, a porous structure in which the polyurethane foam cells 24 communicate with each other. The closed cell ratio (based on ASTM D2856) showing an open cell structure is preferably 20% or less. When the closed cell ratio exceeds 20%, the connectivity of the cells 24 in the foam is lowered. The polyurethane foam having an open cell structure is soft, and the polishing suction pad 11 formed by the foam is damaged by the polishing pressure when polishing the polishing object such as the liquid crystal glass 14. It has a buffering property so that it does not. For this reason, the polyurethane foam is required to have a certain crosslink density and to have resilience.

  A porous flexible polyurethane foam having such an open-cell structure cell 24 is obtained by reacting a raw material of a polyurethane foam containing polyols, polyisocyanates, a foaming agent, a catalyst and a water repellency-imparting agent to foam and cure. Is obtained. Polyols include polyester polyols and polyether polyols, and polyester polyols are preferred in order to develop water repellency due to non-affinity with the water repellency imparting agent. As polyester polyols, in addition to condensation polyester polyols obtained by reacting polycarboxylic acids such as adipic acid and phthalic acid with polyols such as ethylene glycol, diethylene glycol, propylene glycol and glycerin, lactone polyester polyols and polycarbonate systems A polyol is mentioned. Examples of polyether polyols include polypropylene glycol, polytetramethylene glycol, modified products thereof, and compounds obtained by adding alkylene oxide to glycerin. These polyols can change the number of hydroxyl groups and the hydroxyl value by adjusting the kind of raw material components, the molecular weight, the degree of condensation, and the like. Moreover, crosslinking agents, such as 1, 4- butanediol, a trimethylol propane, a pentaerythritol, sorbitol, can also be mix | blended as 1 type of polyols.

  The average hydroxyl value of polyols containing a crosslinking agent is preferably 20 to 100 (mgKOH / g). By using polyols having such a hydroxyl value, it is possible to obtain a polyurethane foam that is excellent in reactivity with polyisocyanates and is appropriately crosslinked. When the average hydroxyl value of polyols exceeds 100 (mgKOH / g), the crosslinking density becomes too high, the foam becomes hard, and the buffering property is lowered. On the other hand, when the average hydroxyl value is less than 20 (mgKOH / g), the hydroxyl value becomes too small, and the crosslinking density of the polyurethane foam tends to be low, and the strength of the foam tends to decrease. Moreover, it is preferable that the average functional group number of polyol containing a crosslinking agent is 2.0-3.0. When this average functional group number is less than 2.0, the crosslinking density of the polyurethane foam is lowered, and the strength of the foam tends to be insufficient. On the other hand, when the average number of functional groups exceeds 3.0, the crosslinking density becomes too high and the foam becomes hard. As a result, the restoring property is deteriorated and the buffering property is lowered.

  Next, polyisocyanates to be reacted with polyols are compounds having a plurality of isocyanate groups, specifically, tolylene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate ( NDI), triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI) and their prepolymers are used.

  Here, the isocyanate index (isocyanate index) of the polyisocyanates is preferably 100 to 120. In other words, the isocyanate index is a percentage of the equivalent ratio of the isocyanate groups of the polyisocyanates to the active hydrogen groups based on the hydroxyl groups of the polyols, crosslinking agent and water repellency imparting agent and the active hydrogen groups of the blowing agent (water). However, the value exceeding 100 means that the isocyanate group is in excess of the active hydrogen group. When the isocyanate index is less than 100, the reaction of polyisocyanates with polyols is insufficient, and the foam tends to be soft and the strength tends to decrease. On the other hand, when the isocyanate index exceeds 120, the foam tends to be hard and the buffering property is lowered.

The foaming agent is for foaming polyurethane into a polyurethane foam. As the foaming agent, water, a low boiling point compound such as methylene chloride, carbon dioxide, or the like is used. Of the foaming agents, water is preferable because of its excellent foaming reaction reactivity and good handling. The blending amount of the foaming agent is 0.03 to 0.07 parts by mass with respect to 100 parts by mass of the polyols in order to suppress the progress of the foaming reaction and obtain a high-density foam by reducing the amount of foaming agent. Is preferred. Thereby, a foam having a density of 600 to 800 kg / m ³ can be obtained. When the blending amount of the foaming agent is less than 0.03 parts by mass, the foaming reaction becomes insufficient, and when it exceeds 0.07 parts by mass, the foaming reaction and the crosslinking reaction become excessive, and the foam tends to become hard.

  The catalyst is for accelerating the urethanization reaction between polyols and polyisocyanates. Such catalysts include N, N ′, N′-trimethylaminoethylpiperazine, triethylenediamine, dimethylethanolamine, tertiary amines such as N-ethylmorpholine, organometallic compounds such as tin octylate, acetates, alkali metal alcoholates Etc. are used.

  The water repellency imparting agent is a compound having a hydroxyl group and a hydrophobic group. Examples of the hydrophobic group include an alkyl group having 6 to 20 carbon atoms. Specific examples of the water repellency-imparting agent include saturated aliphatic monohydric alcohols (monools) such as n-hexanol, n-octanol, n-decanol, and n-stearyl alcohol. In order to sufficiently react the water repellency-imparting agent with the polyisocyanate, it is preferable to react with the isocyanate group of the polyisocyanate in advance and pre-polymerize in advance. The prepolymerization is performed by stirring the water repellency-imparting agent and the polyisocyanates at, for example, room temperature. By using the monohydric alcohol as described above as the water repellency imparting agent, the monohydric alcohol suppresses cross-linking, and the cross-linking density of the resulting foam is reduced. Therefore, even if the density of the obtained foam becomes high, the hardness can be kept low.

  The blending amount of the water repellency imparting agent is preferably 1 to 20 parts by mass per 100 parts by mass of polyols. When the blending amount is less than 1 part by mass, sufficient water repellency cannot be imparted to the surface of the foam, and it becomes difficult to remove the polishing object from the polishing pad after polishing the polishing object. On the other hand, when the blending amount exceeds 20 parts by mass, crosslinking is suppressed, the crosslinking density of the resulting foam is reduced, and the strength is lowered.

  As raw materials for polyurethane foam, in addition to the above components, foam stabilizers such as surfactants, flame retardants such as condensed phosphate esters, antioxidants, plasticizers, UV absorbers, colorants, etc. Is blended.

  Then, the polyurethane foam is produced by reacting and foaming and curing the raw material of the polyurethane foam, but the reaction at that time is complicated, and basically the following reaction is the main component. . That is, addition polymerization reaction (polyurethanation reaction) between polyols and polyisocyanates, foaming (foaming) reaction between polyisocyanates and water as a blowing agent, and crosslinking between these reaction products and polyisocyanates ( Curing) reaction. Here, the above polyols react with polyisocyanates to form the basic skeleton of polyurethane. The cells 24 are formed in the foaming process. However, since the formation speed is slow, the cell membrane is broken and the cells 24 are communicated to produce an open cell polyurethane foam.

The polyurethane foam to be produced preferably has a contact angle of 95 to 115 ° on the surface, that is, the adsorption surface 21. When the contact angle is less than 95 °, sufficient water repellency cannot be imparted to the adsorption surface 21, and the detachability of the object to be polished is lowered. On the other hand, if the contact angle exceeds 115 °, the adsorptivity of the object to be polished decreases. Moreover, it is preferable that the density of a foam is 600-800 kg / m < ³ >, and it is preferable that hardness (Asker A hardness) is 6-15. When the density of the foam is less than 600 kg / m ³ or when the Asker A hardness of the foam is less than 6, the surface of the foam becomes soft and the adsorptivity of the object to be polished tends to decrease. On the other hand, when it exceeds 800 kg / m ³ or when the Asker A hardness of the foam exceeds 15, the foam becomes hard and the buffering property tends to be lowered.

  Now, the operation of this embodiment will be described. The polyurethane foam constituting the polishing suction pad 11 is maintained at a temperature lower than the raw material temperature before foaming or at the initial stage of foaming when the raw material is reacted, foamed and cured. It is manufactured by. At this time, the temperature of the surface of the foam is lower than that of the inside and foaming is suppressed, and a film 20 having a higher density than that of the inside is formed on the surface. Therefore, the surface of the polishing suction pad 11 is kept flat, and the suction force of the liquid crystal glass 14 that is the object to be polished is enhanced during polishing.

  Furthermore, since the water repellency imparting agent such as stearyl alcohol is blended in the raw material of the polyurethane foam, and the water repellency imparting agent has low compatibility with the polyester polyol, it moves to the surface during the reaction and foaming of the raw material. Therefore, water repellency is imparted to the surface of the foam, and the detachability of the liquid crystal glass 14 is enhanced.

The effects exhibited by the above embodiment will be described collectively below.
In the polishing suction pad 11 of the present embodiment, one surface of the plate-like body 19 made of polyurethane foam having an open cell structure is used as the suction surface 21 of the liquid crystal glass 14, and the suction surface 21 has a density from the inside. The foam film 20 is high. For this reason, infiltration of the polishing slurry 18 into the polishing suction pad 11 is suppressed, and formation of minute irregularities on the surface of the polishing suction pad 11 is suppressed. Therefore, the liquid crystal glass 14 can be favorably adsorbed during polishing. Furthermore, since water repellency by the water repellency imparting agent is expressed on the surface of the film 20, water existing between the film 20 surface of the polishing suction pad 11 and the liquid crystal glass 14 is repelled, and after polishing, The liquid crystal glass 14 can be easily detached from the polishing suction pad 11. Thus, the contradictory properties of adsorption and desorption can be exhibited in a well-balanced manner.

  Further, since the contact angle on the suction surface 21 of the polishing suction pad 11 is 95 to 115 °, it has sufficient water repellency so that the liquid crystal glass 14 can be detached from the polishing suction pad 11 after polishing. It can be done easily.

  In the manufacturing method of the suction pad 11 for polishing, when the polyurethane foam raw material containing polyester polyols, polyisocyanates, foaming agent, catalyst and water repellency imparting agent is reacted, foamed and cured, before foaming or in the early stage of foaming And maintaining the temperature lower than the temperature of the raw material. Therefore, the coating 20 can be formed on the surface by setting the temperature at the time of foaming low, and the water repellency can be imparted to the surface by the water repellency imparting agent. Can be easily manufactured.

  In the production of the suction pad 11 for polishing, the water repellency-imparting agent has a hydroxyl group and a hydrophobic group, and the hydroxyl group is reacted with an isocyanate group of a polyisocyanate so as to be prepolymerized in advance. Can be reliably reacted with polyisocyanates and incorporated into the polyurethane backbone.

  In addition, by manufacturing the polishing suction pad 11, the raw material 31 is supplied onto the resin film 28 as a release film, reacted, foamed and cured, and then the resin film 28 is peeled off. The film 20 can be easily formed on the surface of the foam by the resin film 28.

Hereinafter, the embodiment will be described more specifically with reference to examples and comparative examples.
(Examples 1-6)
First, using modified MDI (4,4-diphenylmethane diisocyanate) or polymeric MDI (P-MDI), the water repellency imparting agent shown in Table 1 was mixed, stirred for 1 hour at 500 rpm, and then allowed to stand at room temperature for 24 hours. To prepare a prepolymer (diisocyanate).

表１における略号を以下に示す。

Abbreviations in Table 1 are shown below.

P-MDI: Sumitomo Bayer Urethane Co., Ltd., 44V20 (NCO content 31%)
MDI: Pure MDI (NCO content 33.6%) and carbodiimide-modified pure MDI (NCO content 18.4%) mixed at a ratio of 3 to 7.

Conol 10D: monohydric alcohol having 10 carbon atoms (hydroxyl value is 370 mgKOH / g)
Hv15: Polybutene, manufactured by Nippon Petrochemical Co., Ltd. Next, as raw materials for polyurethane foam, polyols, the prepolymer, water as a blowing agent, and a catalyst were mixed in the blending amounts shown in Table 2. And the polyurethane foam was manufactured with the manufacturing apparatus and manufacturing method which were mentioned above. In that case, the temperature of the cooling box 34 was set to 10 ° C., and the temperature of the heating furnace 35 was set to 70 ° C. When the resin films 27 and 28 were peeled from the obtained polyurethane foam, the film 20 was formed on the surface of the foam. When the thickness of the film 20 was measured with a microscope, it was 0.09 mm (90 μm) in Example 1. The density, Asker A hardness and contact angle of the polyurethane foam were measured by the following methods.

Density (kg / m ³ ): Measured according to JIS K7222: 1999.
Asker A hardness: Measured with an Asker A hardness meter.
Contact angle (°): The contact angle with water on the surface of the polyurethane foam was measured.

  This polyurethane foam was used as a polishing suction pad 11, and was stuck on the surface plate 10 via an adhesive layer 12. Water 13 was passed over the polishing suction pad 11 to adsorb the liquid crystal glass 14 shown below. The following polishing pad 17 bonded to the rotating jig 16 of the following polishing machine was disposed above the liquid crystal glass 14. Then, the rotating jig 16 is lowered to bring the polishing pad 17 into contact with the liquid crystal glass 14, and the polishing slurry 18 in which cerium oxide is dispersed in water is supplied to the polishing portion to polish the surface of the liquid crystal glass 14. . And the position shift of the liquid crystal glass 14 at the time of grinding | polishing, the replacement | exchange ease of the liquid crystal glass 14, and the contamination | pollution property of the liquid crystal glass 14 were evaluated by the method shown below, and those results were shown in Table 2.

Liquid crystal glass 14: diameter 78 mm, thickness 0.7 mm
Polishing machine: Lapmaster, desktop polishing machine LM-15
Polishing pad 17: diameter 40.6 cm (16 inches), thickness 2 mm, manufactured by Rodel Nitta, LP77
Glass positional deviation: The time until the liquid crystal glass 14 was displaced during polishing was measured. And the case where the time was 24 hours or more was made into (circle), and the case where it was less than 24 hours was made into x.

  Easy exchange of glass: When the liquid crystal glass 14 was exchanged after polishing for 24 hours, it was evaluated whether the liquid crystal glass 14 could be easily removed by hand. The case where the liquid crystal glass 14 could be easily removed by hand was marked as ◯, and the case where the liquid crystal glass 14 could not be easily removed by hand was marked as x.

  Contamination of glass: 50% vertical, 50 mm wide, 1 mm thick polyurethane foam is placed on 100 mm square liquid crystal glass 14 and compressed to 50%, and then left in a 70 ° C. constant temperature bath for 24 hours. The presence or absence of deposits was confirmed. The case where the adhered substance could not be visually confirmed was marked with ◯, and the case where the adhered substance could be visually confirmed was marked with x.

表２に示した結果から、実施例１〜６においてはいずれも、ポリウレタン発泡体表面の接触角が９８〜１１０°であり、十分な撥水性を示していた。そして、研磨時における液晶ガラス１４の位置ずれがなく、研磨後における液晶ガラス１４の交換容易性もよく、液晶ガラス１４の汚染性も認められなかった。
（比較例１〜５）
比較例１では、撥水性付与剤を変性ＭＤＩと反応させたプレポリマーを使用せず、変性ＭＤＩをそのまま反応させたほかは、実施例１と同様にして実施した。比較例２においては、撥水性付与剤としてイソブチルアルコールを用いたほかは、実施例１と同様にして実施した。比較例３では、撥水性付与剤としてポリブテンを用いたほかは、実施例１と同様にして実施した。比較例４においては、冷却ボックスの温度を７０℃にしたほかは、実施例１と同様にして実施した。比較例５では、撥水性付与剤をＰ−ＭＤＩと反応させたプレポリマーを使用せず、Ｐ−ＭＤＩをそのまま反応させたほかは、実施例１と同様にして実施した。

From the results shown in Table 2, in each of Examples 1 to 6, the contact angle of the polyurethane foam surface was 98 to 110 °, indicating sufficient water repellency. And there was no position shift of the liquid crystal glass 14 at the time of grinding | polishing, the replacement | exchange ease of the liquid crystal glass 14 after grinding | polishing was good, and the contamination | pollution property of the liquid crystal glass 14 was not recognized.
(Comparative Examples 1-5)
Comparative Example 1 was carried out in the same manner as in Example 1 except that the prepolymer obtained by reacting the water repellency imparting agent with the modified MDI was not used and the modified MDI was reacted as it was. In Comparative Example 2, the same procedure as in Example 1 was performed except that isobutyl alcohol was used as the water repellency-imparting agent. Comparative Example 3 was carried out in the same manner as in Example 1 except that polybutene was used as the water repellency imparting agent. In Comparative Example 4, the same procedure as in Example 1 was performed except that the temperature of the cooling box was set to 70 ° C. Comparative Example 5 was carried out in the same manner as in Example 1 except that the prepolymer obtained by reacting the water repellency imparting agent with P-MDI was not used and P-MDI was reacted as it was.

  And while measuring the density of the obtained polyurethane foam, Asker A hardness, and a contact angle, the positional deviation of the glass at the time of grinding | polishing, the ease of replacement | exchange of glass, and the contamination property of glass were evaluated by the same method as Example 1. did. The results are shown in Table 3.

表３に示した結果から、比較例１及び比較例５では撥水性付与剤を使用しなかったため、所要の吸着性が得られず、液晶ガラス１４の位置ずれが生じた。比較例２においては、撥水性付与剤としてイソブチルアルコールを使用したため、十分な撥水性が発現されず、液晶ガラス１４の位置ずれが生じた。比較例３では、撥水性付与剤としてポリブテンを用いたことから、撥水性が発現されて液晶ガラス１４の位置ずれは認められなかったが、吸着性が強くなり過ぎて液晶ガラス１４の交換が手ではできなかった。比較例４では、冷却ボックス３４の温度を７０℃に上げたため、ポリウレタン発泡体の表面に皮膜２０がほとんど形成されず、液晶ガラス１４の交換時に表面で開口したセル２４が真空状態を呈し、液晶ガラス１４の交換が手ではできなかった。

From the results shown in Table 3, since the water repellency imparting agent was not used in Comparative Example 1 and Comparative Example 5, the required adsorptivity was not obtained and the liquid crystal glass 14 was displaced. In Comparative Example 2, since isobutyl alcohol was used as the water repellency imparting agent, sufficient water repellency was not exhibited, and the liquid crystal glass 14 was displaced. In Comparative Example 3, since polybutene was used as the water repellency imparting agent, water repellency was expressed and no misalignment of the liquid crystal glass 14 was observed, but the adsorptivity became too strong and the liquid crystal glass 14 was easily replaced. It was not possible. In Comparative Example 4, since the temperature of the cooling box 34 was raised to 70 ° C., the film 20 was hardly formed on the surface of the polyurethane foam, and the cells 24 opened on the surface when the liquid crystal glass 14 was replaced exhibited a vacuum state, and the liquid crystal The glass 14 could not be replaced by hand.

In addition, this embodiment can also be changed and embodied as follows.
-The polyurethane foam can be molded so as to have a smooth surface by molding or the like without using the apparatus shown in FIG.

-The plate-like body can be formed into a polygonal plate shape such as a pentagonal plate shape, a disk shape, an elliptical plate shape, or the like.
A magnetic disk, a magneto-optical disk, or the like can be used as an object to be polished.

  A surfactant having a hydrophilic / lipophilic ratio (HLB) of 3 to 6 as a raw material for the polyurethane foam may be blended to increase the hydrophobicity (lipophilicity) of the polyurethane foam.

-As abrasive grains, silica (silicon oxide), alumina (aluminum oxide), or the like can be used.
Further, the technical idea that can be grasped from the embodiment will be described below.

  The method for producing a polishing suction pad according to claim 4 or 5, wherein the water repellency imparting agent is a monohydric alcohol having a hydroxyl group and an alkyl group having 6 to 20 carbon atoms as a hydrophobic group. . In this case, in addition to the effect of the invention according to claim 4 or claim 5, the detachability of the object to be polished can be improved.

The foaming agent is water, and the blending amount of the water is 0.03 to 0.07 parts by mass with respect to 100 parts by mass of polyols. The manufacturing method of the suction pad for polishing as described in a term. In this case, in addition to the effect of the invention according to any one of claims 3 to 5, the density of the polyurethane foam can be 600 to 800 kg / m ³ .

The schematic sectional drawing which shows the state which adhere | attached the suction pad for polishing on the surface plate. Sectional drawing which shows the internal structure of a polyurethane foam typically. Schematic explanatory drawing which shows the cross section of the apparatus which manufactures the plate-shaped object with which both surfaces are smooth.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Adsorption pad for grinding | polishing, 14 ... Liquid crystal glass as a grinding | polishing target object, 18 ... Slurry for grinding | polishing, 19 ... Plate-shaped body, 20, 20a, 20b ... Film | membrane, 21 ... Adsorption surface, 27, 28 ... Release film As a resin film.

Claims (5)

A polishing suction pad for adsorbing a polishing object and polishing the polishing object with a polishing slurry in that state,
One surface of a plate-like body made of polyurethane foam having an open-cell structure is used as an adsorption surface for an object to be polished, and the adsorption surface has a foam film with a higher density than the inside, and the film surface is repellent. A polishing suction pad having water repellency by an aqueous imparting agent, configured to adsorb a polishing object during polishing and to be detached after polishing. The polishing suction pad according to claim 1, wherein a contact angle on the suction surface is 95 to 115 °. A method for producing a suction pad for polishing for adsorbing a polishing object and polishing the polishing object with a polishing slurry in that state,
When a polyurethane foam raw material containing polyester polyols, polyisocyanates, foaming agent, catalyst and water repellency imparting agent is reacted, foamed and cured, it is maintained at a temperature lower than the temperature of the raw material before foaming or at the initial stage of foaming. A method for producing a polishing suction pad. 4. The polishing pad according to claim 3, wherein the water repellency-imparting agent has a hydroxyl group and a hydrophobic group, and the hydroxyl group is reacted with an isocyanate group of a polyisocyanate to be prepolymerized in advance. Production method. 5. The method for producing a polishing suction pad according to claim 3, wherein the raw material is supplied onto a release film to react, foam and cure, and then the release film is peeled off. .

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