Polishing cloth and a method for attaching/detaching the polishing cloth to/from a base plate of a polishing machine

A method for attaching/detaching a polishing cloth to/from a base plate of a polishing machine, the polishing cloth comprising:

• a polishing cloth substrate;
• a pressure-sensitive adhesive layer laminated on one face of the polishing cloth substrate;
• and
• a release sheet attached to the pressure-sensitive adhesive layer in a releasable manner,
• wherein the pressure-sensitive adhesive layer comprises an adhesive composition containing a polymer, the polymer having a first-order melt transition occurring in a temperature range narrower than 15° C.,
• wherein the polymer is a side-chain crystallizable polymer, the side-chain crystallizable polymer being comprised in an amount such that the pressure-sensitive adhesive layer becomes substantially untacky to a base plate of a polishing machine at 20° C. or less and substantially tacky to the base plate of the polishing machine at a temperature higher than 20° C.,
• wherein the method comprises the steps of:
• attaching the polishing cloth to the base plate of the polishing machine by removing the release sheet of the polishing cloth from the pressure-sensitive adhesive layer, and thereafter allowing the pressure-sensitive adhesive layer of the polishing cloth to adhere to the base plate of the polishing machine while keeping the base plate at a temperature T1;
• and
• after use of the polishing cloth, detaching the polishing cloth from the base plate of the polishing machine while cooling the base plate from the temperature T1 to a temperature T2, the temperature T2 being lower than the temperature T1, and
• wherein the temperature T1 is 20° C. or higher, and the temperature T2 is below 20° C.

A polishing cloth comprising:

• a polishing cloth substrate;
• a pressure-sensitive adhesive layer laminated on one face of the polishing cloth substrate;
• and
• a release sheet attached to the pressure-sensitive adhesive layer in a releasable manner,
• wherein the pressure-sensitive adhesive layer comprises an adhesive composition which:
• (i) contains 40 to 100% by weight of at least one crystallizable polymer which (a) begins to melt at a temperature T0, and (b) completes melting at a temperature Tm, which is at most (T0+15° C.);
• (ii) is substantially untacky to a base plate of a polishing machine at temperatures below T0;
• (iii) becomes substantially tacky to the base plate of the polishing machine when heated from a temperature below T0 to a temperature above Tm;
• (iv) becomes substantially untacky to the base plate of the polishing machine when cooled below the temperature T0 from the temperature above Tm, and
• the crystallizable polymer is a side-chain crystallizable polymer containing the following repeating unit of the formula:
• wherein M is a group forming part of the backbone of the polymer, S is a spacer unit, and C is a crystallizable group, and
• wherein the temperature T0 is below 20° C., and the temperature re Tm is 20° C. or higher.

A polishing cloth comprising:

• a polishing cloth substrate;
• an adhesive layer laminated on the polishing cloth substrate;
• a film laminated on the adhesive layer;
• a pressure-sensitive adhesive layer laminated on the film;
• and
• a release sheet attached to the pressure-sensitive adhesive layer in a releasable manner,
• wherein the pressure-sensitive adhesive layer comprises an adhesive composition containing a polymer, the polymer having a first-order melt transition occurring in a temperature range narrower than 15° C.,
• wherein the polymer is a side-chain crystallizable polymer, the side-chain crystallizable polymer being comprised in the adhesive composition in the range of about 40% by weight to about 100% by weight;
• the side-chain crystallizable polymer being comprised in an amount such that the pressure sensitive adhesive becomes substantially untacky to the base plate of a polishing machine at 20 degrees Celsius or less and substantially tacky to the base plate of the polishing machine at a temperature higher than 20 degrees Celsius.