U.S. patent application number 15/733073 was filed with the patent office on 2021-12-02 for polishing pad.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Masaaki Ichikawa, Shoichi Masuda.
Application Number | 20210370475 15/733073 |
Document ID | / |
Family ID | 1000005825038 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210370475 |
Kind Code |
A1 |
Ichikawa; Masaaki ; et
al. |
December 2, 2021 |
POLISHING PAD
Abstract
Object: Providing a polishing pad that is deformable with a
smaller force. Solution: A polishing pad (1) according to an aspect
of the invention includes a substrate (2) made of a piece of
non-woven fabric. The substrate (2) has a flat-plate shape
extending in a first direction perpendicular to a thickness
direction and in a second direction perpendicular to both the
thickness direction and the first direction. The substrate (2) is
divided into a plurality of blocks (3) arranged in the second
direction and each extending in the first direction. A boundary
portion (4) extending in the first direction is formed between each
pair of the blocks (3), and a plurality of slits (6) are formed in
the boundary portion (4). Each of the slits (6) is formed through
the substrate (2) in the thickness direction and extends in first
direction. The plurality of slits (6) that exist in the boundary
portion (4) are spaced apart from each other in the first
direction. A pair of the blocks (3) that are next to each other in
the second direction are connected to each other by a connection
portion (7) formed between the slits (6).
Inventors: |
Ichikawa; Masaaki;
(Kanagawa, JP) ; Masuda; Shoichi; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
1000005825038 |
Appl. No.: |
15/733073 |
Filed: |
October 31, 2018 |
PCT Filed: |
October 31, 2018 |
PCT NO: |
PCT/IB2018/058558 |
371 Date: |
May 7, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24D 15/04 20130101;
B24D 11/02 20130101 |
International
Class: |
B24D 15/04 20060101
B24D015/04; B24D 11/02 20060101 B24D011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2017 |
JP |
2017-214759 |
Claims
1. A polishing pad comprising a substrate made of a piece of
non-woven fabric, wherein the substrate has a flat-plate shape
extending in a first direction perpendicular to a thickness
direction and in a second direction perpendicular to both the
thickness direction and the second direction; the substrate is
divided into a plurality of blocks arranged in the second direction
and each extending in the first direction; a boundary portion
extending in the first direction is formed between a pair of the
blocks, a plurality of slits are formed in the boundary portion
through the substrate in the thickness direction and each of the
slits extends in the first direction, the plurality of slits that
exist in the boundary portion are spaced apart from each other in
the first direction; and a pair of the blocks that are next to each
other in the second direction are connected to each other by a
connection portion formed between the slits.
2. The polishing pad according to claim 1, wherein the connection
portion of the boundary portion formed on a first side, in the
second direction, of the block is located at a different position
in the first direction from the position of the connection portion
of the boundary portion formed on a second side of the block.
3. The polishing pad according to claim 1, wherein the substrate
has a bending strength in the second direction that is from 10 to
80% of the bending strength in the first direction of the
substrate.
4. The polishing pad according to claim 1, wherein the block has a
dimension in the second direction ranging from 2 to 40 mm, the slit
has a dimension in the first direction ranging from 5 to 50 mm, and
the connection portion has a dimension in the first direction
ranging from 5 to 50 mm.
5. A polishing pad including a substrate made of a piece of
non-woven fabric, wherein the substrate has a flat-plate shape
extending in a first direction perpendicular to a thickness
direction and in a second direction perpendicular to both the
thickness direction and the first direction, in the substrate, a
slit extending in the thickness direction from a first principal
surface in the thickness direction and extending in the first
direction in the principal surface is formed, and a plurality of
the slits are formed in the second direction.
Description
TECHNICAL FIELD
[0001] The invention relates to a polishing pad.
BACKGROUND ART
[0002] There is a known polishing pad that includes a substrate
made from a non-woven fabric. For instance, the polishing pad
disclosed in Patent Document 1 is used for scouring a target object
to remove dirt on the target object.
PRIOR ART DOCUMENTS
Patent Documents
[0003] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2011-189189
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0004] In some cases where a worker uses a polishing pad for
cleaning, the polishing pad has to be deformed (bent) to be fit to
the shape of the target object. The worker scours the target object
while keeping the polishing pad deformed (bent). A worker using a
polishing pad of the above-described type has to apply a force to
deform (bend) the polishing pad and to keep the polishing pad
deformed (bent). Hence, there has been a demand for a polishing pad
that is deformable (bendable) by a smaller force to make the
scouring work easier.
Means for Solving the Problem
[0005] A polishing pad according to an aspect of the invention
includes a substrate made of a piece of non-woven fabric. The
substrate has a flat-plate shape extending in a first direction
perpendicular to a thickness direction and in a second direction
perpendicular to both the thickness direction and the first
direction. The substrate is divided into a plurality of blocks
arranged in the second direction and each extending in the first
direction. A boundary portion extending in the first direction is
formed between each pair of the blocks, and a plurality of slits
are formed in the boundary portion. Each of the slits is formed
through the substrate in the thickness direction and extends in
first direction. The plurality of slits that exist in the boundary
portion are spaced apart from each other in the first direction. A
pair of the blocks that are next to each other in the second
direction are connected to each other by a connection portion
formed between the slits.
Effect of the Invention
[0006] The invention provides a polishing pad that is deformable
(bendable) with a smaller force.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view illustrating a polishing pad
according to an embodiment.
[0008] FIG. 2A is a drawing illustrating the polishing pad viewed
from an X-axis direction. FIG. 2B is a drawing illustrating the
polishing pad in a deformed (bent) state viewed from the X-axis
direction.
[0009] FIG. 3 is a drawing illustrating a state of slits of the
deformed (bent) polishing pad viewed from a thickness
direction.
[0010] FIG. 4 is a drawing illustrating a model used for
determining a Y-axis-direction dimension of each block.
[0011] FIG. 5A is a drawing illustrating a polishing pad according
to a comparative example viewed from the thickness direction. FIG.
5B is a drawing illustrating the polishing pad according to the
comparative example viewed from the X-axis direction. FIG. 5C is a
drawing illustrating the polishing pad in a deformed (bent) state
according to the comparative example viewed from the X-axis
direction.
[0012] FIG. 6A and FIG. 6B are drawings illustrating polishing pads
according to modified examples viewed from the thickness
direction.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] An embodiment of the invention will be described below with
reference to the attached drawings. Note that, in the following
descriptions, the same reference symbols have been assigned to
elements that are the same or equivalent, and that redundant
descriptions thereof have been omitted.
[0014] A polishing pad 1 according to an embodiment of the
invention will be described below with reference to FIG. 1. FIG. 1
is a perspective view illustrating a polishing pad. As illustrated
in FIG. 1, the polishing pad 1 includes a substrate 2. In this
embodiment, a direction perpendicular to a thickness direction of
the substrate 2 is defined as an X-axis direction (first direction)
whereas a direction perpendicular to both the thickness direction
and the X-axis direction is defined as an Y-axis direction (second
direction). The substrate 2 has a flat-plate shape extending in
both the X-axis direction and in the Y-axis direction. The
substrate 2 has principal surfaces 2c and 2d, which are opposite to
each other in the thickness direction. In FIG. 1, the substrate 2
has its longer side extending in the X-axis direction and its
shorter side extending in the Y-axis direction. The shape of the
substrate 2 is not particularly limited. In the substrate 2, the
proportion of the side in the X-axis direction to the side in the
Y-axis direction may be appropriately changed if necessary. The
size of the polishing pad 1 may be one that allows the worker to
hold the polishing pad 1 while the worker is working with the
polishing pad 1. For instance, the polishing pad 1 may have a
thickness ranging from 20 to 40 mm and a dimension ranging from 100
to 150 mm both in the X-axis direction and in the Y-axis
direction.
[0015] Firstly, some illustrative examples of the substrate 2 are
described below. The substrate 2 of this type is one using a
water-soluble binder. The substrate 2 is made of a piece of
non-woven fabric. The non-woven fabric has an abrasive coat
configured to hold abrasive particles. Some non-woven webs suitable
for use in abrasive cleaning articles are not limited to particular
ones, and are made of an air-laid, a carded, a stitch-bonded, a
spun-bonded, a wet-laid, or a melt-blown structure. Some examples
of the fibers suitable for use in abrasive cleaning articles are
natural fibers, synthetic fibers, and mixtures thereof. Some
preferred fibers are synthetic fibers made from polyester (e.g.,
polyethylene terephthalate), nylon (e.g., hexamethylene adipamide
and polycaprolactam), polypropylene, acryl (formed from
acrylonitrile polymer), rayon, cellulose acetate, polyvinylidene
chloride-vinyl chloride copolymer, vinyl chloride-acrylonitrile
copolymer, or the like. Some examples of the suitable natural
fibers are cotton, wool, jute, and linen fibers. The fibers to be
used may be new, unused fibers. Alternatively, waste fibers may be
used as well, for instance, those recycled fibers obtained by
cutting garments and those obtained from carpet manufacturing
processes, fiber manufacturing processes, or textile fiber
manufacturing processes. The fiber material may be uniform fibers,
or may be composite fibers such as conjugated fibers (e.g., co-spun
sheath-core fiber). Providing an article whose web contains
different fibers in different portions (e.g., a first web portion,
a second web portion, and an intermediate web portion) is also
within the scope of the invention. The web fiber may preferably be
stretched and crimped. Alternatively, the web fiber may be
continuous filaments formed by an extrusion molding process and may
be continuous fibers.
[0016] The abrasive coat is designed to make the substrate 2 hold
the abrasive particles and to fix the abrasive particles to the
substrate 2. The abrasive coat contains a water-soluble binder.
When the polishing pad 1 is used, the water-soluble binder is
exposed to a solvent. Until that time, the water-soluble binder is
solidified so that the abrasive particles can be held by and fixed
to the non-woven fabric of the substrate 2. The solvent is one that
is used for cleaning. Once the solvent starts to solve the
water-soluble binder, the abrasive particles are released from the
polishing pad 1. The water-soluble binder may be an oligomer or a
polymer, or may contain copolymers and a blend thereof. Unlimited
examples of polymers and copolymers that are suitable for use as
the water-soluble binder are: polyethylene glycol, polyvinyl
pyrrolidone, polyvinyl pyrrolidone/vinyl acetate copolymer,
polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose
starch, polyethylene oxide, polyacrylamide, polyacrylic acid,
cellulose ether polymer, polyethyloxazoline, polyethylene oxide
ester, copolymer of polyethylene oxide ester and polypropylene
oxide, polyethylene oxide urethane, and copolymer of polyethylene
oxide urethane and polypropylene oxide.
[0017] The water-soluble binder may be a surfactant. In addition,
the water-soluble binder may include a combination of various
water-soluble binders containing a surfactant as a component. In
addition, the water-soluble binder may include a combination of
various surfactants.
[0018] Some of the surfactants useful in the invention are those
that are easily soluble in water. In addition, the surfactant
provides excellent foamability, cleaning ability, oil-fat removing
property in ordinary cleaning use in households. The surfactant
helps remove coloring stains, grease, oil, soil, dirt, and
deposits.
[0019] Some examples of the surfactants used for the abrasive
cleaning article of the invention are one or more kinds of anionic
surfactants, cationic surfactants, nonionic surfactants, and
amphoteric surfactants, as well as combinations of such
surfactants. Desirable surfactants are those gentle on the skin of
the user and nontoxic. In a blend of one or more kinds of anionic
surfactants, cationic surfactants, nonionic surfactants, and/or
amphoteric surfactants, the use of an anionic surfactant in a
higher concentration is desirable for enhanced foamability and
cleaning ability. This, however, is within the scope of the
invention.
[0020] The abrasive particles are releasably fixed to the non-woven
fabric of the substrate 2 by the water-soluble binder. Examples of
the abrasive particles used in the manufacturing of the article
according to the invention include all the known abrasive
materials, combinations and aggregates of such abrasive materials.
Some examples of softer abrasive materials are: inorganic materials
such as flint, silica, pumice, and calcium carbonate; organic
polymer materials such as polyester, polyvinyl chloride,
methacrylate, methyl methacrylate, polycarbonate, and polystyrene;
and combinations of some of the above-mentioned materials. These,
however, are not the only examples. Some examples of harder
abrasive materials are: aluminum oxides such as aluminum oxide,
heat-treated aluminum oxide, and white aluminum oxide; silicon
carbide; alumina zirconia; diamond; ceria, cubic boron nitride;
garnet; and combinations of some of the above-mentioned materials.
These, however, are not the only examples.
[0021] In addition to the water-soluble binder and the abrasive
particles, the abrasive coat may contain colorants, perfumes,
fragrant oils, preservatives, humectants, anti-foaming agents,
coupling agents, suspending agents, pigments, and antibacterial
additives. Such additional components are well known to the persons
in the relevant technical field.
[0022] Secondly, different illustrative examples of the substrate 2
are described below. The substrate 2 of this type is one using a
thermosetting adhesive as the binder. Some preferred non-woven
fabrics are those made from thermoplastic organic fibers such as
polyamide (e.g., nylon 6 and nylon 6,6 made from polycaprolactam
and/or polyhexamethyl adipamide), polyolefin (e.g., polypropylene
and polyethylene), polyester (e.g., polyethylene terephthalate),
and polycarbonate. Commonly used non-woven fabrics are those made
from nylon and polyester fibers.
[0023] In general, the fiber has a thickness (diameter) ranging
from 19 to 250 .mu.m, approximately. In general, the non-woven
fabric has a thickness ranging from 2 to 50 mm, approximately. Once
arranged in place, the fibers are bonded to one another at
intersections and/or contact points by frictional forces, adhesive
forces, etc. The bonding of fibers may be achieved by melting the
fibers or by the use of a special adhesive agent.
[0024] Adhesive agents are used for boding the fibers of the
non-woven fabric to one another or for bonding the fibers of the
non-woven fabric to the abrasive particles. A single adhesive agent
may be used both for bonding the fibers of the non-woven fabric to
one another and for bonding the fibers of the non-woven fabric to
the abrasive particles. Alternatively, different adhesive agents
may be used for the above-mentioned different purposes. When a
single adhesive agent is used, the bonding of the fibers of the
non-woven fabric to each other and the bonding of the fibers of the
non-woven fabric to the abrasive particles may be carried out
simultaneously in the manufacturing process.
[0025] A first adhesive agent to be used for bonding the fibers of
the non-woven fabric to one another may be such thermosetting
adhesive agents as aqueous suspensions and organic solvent
solutions of epoxy, melamine, phenol, isocyanate and isocyanurate
resins, or such rubber-based polymer solutions or suspensions as
SBR, SBS, and SIS.
[0026] The non-woven fabric is formed by hardening the adhesive
agents applied by a method such as a dip coating, a roll coating,
and a spray coating.
[0027] The method of manufacturing the substrate 2 is not
particularly limited. For instance, the substrate 2 may be formed
by, firstly, stacking a plurality of fiber sheets one upon another
to form a layered body and then sticking the sheets in the layered
body together with an adhesive agent. Alternatively, the substrate
2 may be formed by collecting extruded fibers together, then
sticking the fibers together, and then cutting the solid layered
body with a die.
[0028] The substrate 2 is divided into a plurality of blocks 3
arranged in the Y-axis direction and each extending in the X-axis
direction. The blocks 3 refer to some areas of the substrate 2
located between a first end portion 2a and a second end portion 2b
in the X-axis direction. The blocks 3 are the areas with no slits 6
extending in the X-axis direction (details of the slits 6 will be
described later). In the substrate 2, each of the blocks 3 extends
in a band shape between the end portion 2a and the end portion 2b.
While the substrate 2 is in a deformed state, the blocks 3 become
the main areas that are brought into contact with the target object
to polish the surface of the target object. Each of the blocks 3 is
defined to have a predetermined width in the Y-axis direction. How
to set the pitch at which the blocks 3 are arranged will be
described later.
[0029] Between a pair of the blocks 3, a boundary portion 4
extending in the X-axis direction is formed. Each of the boundary
portion 4 has a plurality of slits 6 each of which is formed
through the substrate 2 in the thickness direction and each of
which extends in the X-axis direction. Each of the slits 6 extends
in the thickness direction from the principal surface 2c to the
principal surface 2d. The slits 6 are formed by: providing a tool
having a plurality of plate-shaped blade members standing on a base
member; and then pressing the substrate 2 against the tool to allow
the blade members to penetrate the substrate 2. In each of the
boundary portions 4, the plurality of slits 6 are spaced apart from
one another in the X-axis direction. The portion between one slit 6
and another slit 6 serves as a connection portion 7 configured to
connect one block 3 to another block 3. To put it differently, a
pair of the blocks 3 that are next to each other in the Y-axis
direction are connected to each other by the connection portion 7
formed between the slits 6.
[0030] In FIG. 1, some of the boundary portions 4 are indicated by
imaginary lines. Each of the boundary portions 4 is a straight line
extending straight in the X-axis direction. A plurality of the
slits 6 and a plurality of the connection portions 7 are
alternately arranged in each of the boundary portion 4. To put it
differently, each of the "boundary portions" corresponds to an
imaginary line drawn to overlap the slits 6 when viewed in the
thickness direction and extending to the end portions 2a and 2b.
Hence, each of the boundary portions 4 refers to an imaginary line
configured to virtually separate a block 3 from another block 3.
Each of the "slits" refers to a cut formed in the substrate 2.
While the substrate 2 is in a normal state (the state illustrated
in FIG. 1), edge portions 6a and 6b of each slit (see FIG. 2 and
FIG. 3) are in contact with or adjacent to each other in the
principal surface 2c. If a force is applied to widen each of the
blocks 3 in the Y-axis direction, the distance between the edge
portions 6a and 6b of each slit 6 increases to separate the edge
portions 6a and 6b separated from each other in the principal
surface 2c. Each of the "connection portion" refers to a portion of
the imaginary line of the boundary portion 4. The portion has no
slit 6. Even if a force is applied to widen each of the blocks 3 in
the Y-axis direction, the connection portion 7 fixes the blocks 3
that are next to each other by preventing the blocks 3 from
departing from each other and thus by leaving no such opening as
the slit 6.
[0031] As such, by forming slits in some portions of the substrate
2, the deformation (bending) of the substrate 2 in the Y-axis
direction by a worker leaves the substrate 2 in a state where
openings appear at the positions of the slits 6 as illustrated in
FIG. 2 and FIG. 3. At each slit 6, an opening is formed in the
substrate 2 so that the edge portions 6a and 6b located on the
outer peripheral side for the deformation (bending) can go away
from each other. In contrast, if the substrate 2 is deformed (bent)
in the X-axis direction, the substrate 2 is deformed (bent) without
leaving any opening at the positions of the slits 6. Hence, the
worker can deform (bend) the substrate 2 more easily in the Y-axis
direction than in the X-axis direction. For instance, the substrate
2 may have a bending strength in the Y-axis direction that is from
10 to 80%, preferably from 15 to 50%, of the bending strength of
the substrate 2 in the X-axis direction. The bending strength is
obtained by measurement using a Gurley-type bending stiffness
tester and following a measurement method that conforms to the
bending repulsion method A of JIS L-1096 and JAPAN TAPPI NO. 40.
Note that when the polishing pad 1 is deformed (bent), a
spring-back force (repulsive force) is generated in the polishing
pad 1 itself. The repulsive force returns the polishing pad 1 to a
substantially flat state when the force bending the polishing pad 1
is released. In addition, the repulsive force has an effect to
allow the polishing pad 1 to fit closely to (stick to) the palm of
the worker while the worker is working with the polishing pad
1.
[0032] In this embodiment, the connection portions 7 formed in the
boundary portion 4 located on a first side, in the Y-axis
direction, of a block 3 are located at different positions in the
X-axis direction from the positions of the connection portions 7
formed in the boundary portion 4 located on a second side, in the
Y-axis direction, of the same block 3. Note that the phrase
"located at different positions" only means that the position of
the center, in the Y-axis direction, of one connection portion 7 is
different from the corresponding position of the other connection
portion 7. Hence, a portion, in the Y-axis direction, of one
connection portion 7 may overlap a portion of the other connection
portion 7. The slits 6 formed in the boundary portion 4 located on
a first side, in the Y-axis direction, of a block 3 are located at
different positions in the X-axis direction from the positions of
the slits 6 formed in the boundary portion 4 located on a second
side, in the Y-axis direction, of the same block 3. To put it
differently, of every two adjacent boundary portions 4, one
boundary portion 4 has slits 6 that form a zigzag pattern together
with the slits 6 of the other boundary portion 4. A structure like
the above-described one where a plurality of slits 6 are arranged
in a zigzag pattern may be referred to as a skip slit structure. In
this embodiment, the slits 6 in the two boundary portions 4 located
at every other line are located at the identical positions to one
another, and so are the boundary portions 4 in such two boundary
portions 4. Hence, a zigzag pattern of the slits 6 is formed by
sets of boundary portions 4, each set including a pair of the
boundary portions 4.
[0033] Each block 3, each slit 6, and each connection portion 7 in
the above-described configuration may have dimensions that are not
particularly limited but set in the following way, for instance.
The dimension, in the Y-axis direction, of each block 3 may range
from 2 to 40 mm, preferably from 2 to 20 mm. The dimension, in the
X-axis direction, of the each slit 6 may range from 5 to 50 mm,
preferably from 10 to 30 mm. The dimension, in the X-axis
direction, of each connection portion 7 may range from 5 to 50 mm,
preferably from 10 to 30 mm.
[0034] Now, descriptions will be provided below concerning an
exemplar method of setting the dimension, in the Y-axis direction,
of each block 3. For instance, when a target object 30 having a
circular cross section as illustrated in FIG. 4 is polished by the
use of the polishing pad 1, the polishing pad 1 is desirably in
contact with the target object 30 at least 8 positions located in
the circumferential direction. The model illustrated in FIG. 4
assumes that when the substrate 2 of the polishing pad 1 is
deformed (bent) to cover the target object 30, each block 3 becomes
substantially straight and the substrate 2 is bent at the positions
of the boundary portions 4. In this case, the substrate 2 is
brought into contact with the target object 30 at predetermined
points of the blocks 3. In FIG. 4, an octagon is drawn with
dashed-dotted lines on the outer circumference of the target object
30 to indicate the polishing surface of the substrate 2. Here, when
the target object 30 has a diameter of 50 mm, a dimension of 19.6
mm is obtained by dividing equally the outer circumference of the
target object 30 into 8.
[0035] Hence, the dimension, in the Y-axis direction, of each block
3 may preferably be not greater than 20 mm, approximately.
[0036] Next, description will be provided concerning advantageous
effects of the polishing pad 1 according to this embodiment.
[0037] The polishing pad 1 is including the substrate 2 made of a
piece of non-woven fabric. The substrate 2 has a flat-plate shape
extending in the X-axis direction perpendicular to the thickness
direction and in the Y-axis direction perpendicular to both the
thickness direction and the X-axis direction. The substrate 2 is
divided into a plurality of the blocks 3 arranged in the Y-axis
direction and each extending in the X-axis direction. The boundary
portion 4 extending in the X-axis direction is formed between each
pair of the blocks 3, and a plurality of the slits 6 are formed in
the boundary portion 4. Each of the slits 6 is formed through the
substrate 2 in the thickness direction and extends in the X-axis
direction. The plurality of slits 6 that exist in the boundary
portion 4 are spaced apart from each other in the X-axis direction.
A pair of the blocks 3 that are next to each other in the Y-axis
direction are connected to each other by the connection portion 7
formed between the slits 6.
[0038] For instance, a polishing pad 100 according to a comparative
example illustrated in FIG. 5 has no such slits as those that are
provided in this embodiment. In the case of the comparative
example, when the worker tries to deform (bend) the polishing pad
100, a resistance force against the bending of the substrate 2 is
generated. Hence, the worker needs to apply a greater force to
deform (bend) the polishing pad 100. In contrast, the polishing pad
1 according to this embodiment has slits 6 formed in the boundary
portions 4 between the blocks 3 of the substrate 2 and each
extending in the X-axis direction. When a force is applied to bend
the substrate 2 in the Y-axis direction, the substrate 2 leaves
openings that easily widen at the positions of the slits 6. Hence,
when the worker tries to deform (bend) the polishing pad 1, the
substrate 2 can be deformed (bent) easily by allowing the slits 6
to widen. In addition, even if such slits 6 are formed, the
boundary portions 4 include the connection portions 7 configured to
connect the blocks 3 to each other prevent the blocks 3 from being
cut off from each other. Hence, only a reduced force is needed to
deform (bend) the polishing pad 1.
[0039] The connection portions 7 formed in the boundary portion 4
located on a first side, in the Y-axis direction, of a block 3 may
be located at different positions in the X-axis direction from the
positions of the connection portions 7 formed in the boundary
portion 4 located on a second side, in the Y-axis direction, of the
same block 3. For instance, if, as illustrated in FIG. 6A later,
the connection portions 7 that are next to each other in the Y-axis
direction are formed at the identical positions to each other in
the X-axis direction, a greater resistance force against the
bending of the substrate 2 is generated at positions where the
connection portions 7 are contiguously formed as described above.
In contrast, if the connection portions 7 that are next to each
other in the Y-axis direction are located at different positions,
in the X-axis direction, from each other, the connection portions 7
can be dispersed to prevent the resistance force against the
bending from becoming greater.
[0040] The substrate 2 may have a bending strength in the Y-axis
direction that is from 10 to 80% of the bending strength of the
substrate 2 in the X-axis direction. In this case, the worker can
bend easily the polishing pad 1 to work with the polishing pad
1.
[0041] The dimension, in the Y-axis direction, of the block 3 may
range from 2 to 40 mm, the dimension, in the X-axis direction, of
the slit 6 may range from 5 to 50 mm, and the dimension, in the
X-axis direction, of the connection portion 7 may range from 5 to
50 mm. In this case, the worker can bend easily the polishing pad
1. In addition, a sufficient strength of the polishing pad is
secured.
[0042] The polishing pad 1 is including the substrate 2 made of a
piece of non-woven fabric. The substrate 2 has a flat-plate shape
extending in the X-axis direction perpendicular to the thickness
direction and in the Y-axis direction perpendicular to both the
thickness direction and the X-axis direction. In the substrate 2, a
slit 6 extending in the thickness direction from the first
principal surface 2c in the thickness direction and extending in
the X-axis direction in the principal surface 2c is formed and a
plurality of slits 6 are formed in the Y-axis direction.
[0043] In the polishing pad 1, the substrate 2 has the slit 6
extending in the thickness direction from the first principal
surface 2c in the thickness direction and extending in the X-axis
direction in the principal surface 2c. When a force is applied to
bend the substrate 2 in the Y-axis direction, the substrate 2
leaves an opening that easily widens at the position of the slit 6.
In addition, a plurality of slits 6 are formed in the Y-axis
direction. Hence, the slits 6 are opened at a plurality of
positions in the Y-axis direction. The entire substrate 2 can thus
be deformed (bent) easily. Accordingly, only a reduced force is
needed to deform (bend) the polishing pad 1.
[0044] The present invention is not intended to be limited to the
embodiment described above, but allows appropriate modifications
when necessary.
[0045] The arrangement of the slits 6 is not limited to those
described in the above-described embodiment. For instance, in the
polishing pad 1 illustrated in FIG. 6A, the connection portions 7
formed in the boundary portion 4 located on a first side, in the
Y-axis direction, of a block 3 are identical positions, in the
X-axis direction, to the corresponding connection portions 7 formed
in the boundary portion 4 located on a second side, in the Y-axis
direction, of the same block 3. As such, the slits 6 do not have to
be arranged in a zigzag pattern. In addition, in the embodiment
illustrated in FIG. 1, every two boundary portions 4 form a set and
sets of such boundary portions 4 form a zigzag pattern of slits 6.
In lieu of this way of forming a zigzag pattern, an alternative way
of forming a zigzag pattern may be employed where as illustrated in
FIG. 6B, even more boundary portions 4 form a set, and the sets of
such boundary portions 4 form a zigzag pattern of slits 6. The
arrangement pattern of the slits 6, however, may be irregular
one.
[0046] In addition, the slits 6 in the above-described embodiment
are formed through the substrate 2. In lieu of this configuration,
the slits 6 may be formed not through the substrate 2. For
instance, each slit 6 may extend in the thickness direction from
the principal surface 2c of the substrate 2 to stop at a
predetermined position in the substrate 2 without reaching the
principal surface 2d.
[0047] In the above-described embodiment, each of the slits is
formed to extend only in the X-axis direction. In addition to
these, an extra slit or extra slits may be formed to extend in the
Y-axis direction. In such a case, the polishing pad can be deformed
(bent) easily in the X-axis direction, as well.
[0048] In the above-described embodiment, a
rectangular-plate-shaped member is employed as an exemplar
substrate of the polishing pad. The shape of the substrate,
however, is not particularly limited. The slit structure may be
applied to any type of substrate. For instance, the slit structure
may be applied to a flap brush, a unitized wheel, a unitized pad, a
bevel, a wheel, and the like.
* * * * *