JP5741398B2 - Mold cleaning sheet - Google Patents

Description

  The present invention relates to a mold cleaning sheet used for cleaning a mold surface of a molding mold.

  In the step of resin-sealing a semiconductor element by transfer molding, resin molding using a mold is usually repeated. As the number of repetitions (the number of shots) increases, dirt such as components, flashes, and dust that have exuded from the resin accumulate on the mold surface, particularly the cavity surface. Such dirt deteriorates the releasability when the molded product is taken out from the mold, and causes rough skin on the surface of the molded product. Therefore, the mold surface (cavity surface) of the mold is cleaned every fixed number of molding repetitions (number of shots).

  As this cleaning method, a method using a mold cleaning sheet has been proposed (for example, see Patent Documents 1 and 2). As shown in FIG. 14, in this mold cleaning sheet, a plurality of strip-shaped mold cleaning members 20 are arranged in parallel with a gap on one or both sides (one side in FIG. 14) of the sheet-like substrate 1. It has been established. When cleaning the mold, the mold cleaning sheet is sandwiched between the upper mold and the lower mold, and the mold is clamped in that state. Thereby, the mold cleaning member 20 of the mold cleaning sheet is filled in the cavity. At this time, since the air in the cavity escapes from the gap between the adjacent band-shaped mold cleaning members 20, the mold cleaning member 20 is filled to every corner in the cavity. Then, by performing heat molding in this state, dirt on the cavity surface is attached to the mold cleaning member 20, and thereafter, the mold cleaning sheet is removed, and the dirt together with the mold cleaning member 20 is removed from the mold. Remove from mold surface (cavity surface).

JP 2007-196586 A JP 2008-132759 A

  The mold cleaning sheet is excellent in filling property (cleaning property) of the mold cleaning member 20 because the air clearance in the cavity is good because the gap for air bleeding is formed as described above. However, depending on the case, wrinkles may occur or warp. When a mold is cleaned using such a mold cleaning sheet, the dimension of the mold cleaning sheet is not sufficient to the dimension of the mold, or the mold cleaning sheet is bent, and the mold cleaning member 20 has a cavity. In some cases, the filling ability of the ink was reduced and cleaning was insufficient.

  Therefore, as a result of the inventor pursuing the cause of the wrinkles and warping, the cause is that the belt-shaped mold cleaning member 20 is in the longitudinal direction depending on the size, shape, component, etc. of the mold cleaning member 20. It turned out to be shrinking along. That is, the mold cleaning sheet is formed on the mold cleaning member 20 by using an unvulcanized rubber composition or a thermosetting resin composition on one or both sides of the sheet-like substrate 1 as a material. However, after demolding, due to the thermal residual stress of the molded band-shaped mold cleaning member 20, as described above, the band-shaped mold cleaning member 20 is moved along the longitudinal direction. As a result, the mold cleaning sheet was found to wrinkle and warp.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a mold cleaning sheet that does not cause wrinkles or warpage and has high cleaning properties.

  In order to achieve the above object, a mold cleaning sheet of the present invention is a mold cleaning sheet used for cleaning a mold in which a cavity having an oval or rectangular opening is formed. A plurality of belt-shaped mold cleaning members made of an unvulcanized rubber-based composition or a thermosetting resin-based composition are arranged in parallel with a gap on at least one surface of the material. The members are cut in the longitudinal direction at predetermined intervals to be formed in a column made up of a plurality of block bodies, the length of the block bodies is set within a range of 3 to 50 mm, and the blocks are made up of the plurality of block bodies. In the column, the gap between the block bodies is set to a dimension of 0.1 mm or more and less than the width of the mold cleaning member, and the mold cleaning is performed. The gap between the mold cleaning members adjacent in the width direction of the material is set to a dimension that is 1/2 or more of the width of the mold cleaning member and less than or equal to the width of the mold cleaning member, and The mold cleaning member has a width of 1 mm or more and is set to a dimension of 4/5 or less of the lateral width of the oval or square cavity opening.

  The present inventor does not cause wrinkles or warping while taking advantage of the high cleaning property of the above-described mold cleaning sheet in which a plurality of belt-shaped mold cleaning members are arranged in parallel with a gap. In order to do so, research was repeated. As a result, when the strip-shaped mold cleaning member is cut at a predetermined interval in the longitudinal direction and formed into a series of blocks, a contraction due to the thermal residual stress of the mold cleaning member is caused by the entire strip-shaped mold. Instead, it was found that the shrinkage of the block body was reduced because it was a partial block. Furthermore, research was conducted on the appropriate dimensions and the like of the mold cleaning member of the block body. As a result, the length of the block bodies is set within a range of 3 to 50 mm, and the gap between the block bodies is 0.1 mm or more in the column composed of the plurality of block bodies, and the mold cleaning is performed. The gap between the mold cleaning member which is set to a dimension less than the width of the member and is adjacent to the mold cleaning member in the width direction is 1/2 or more of the width of the mold cleaning member, The width of the mold cleaning member is set to a dimension equal to or smaller than the width of the mold cleaning member, and the width of the mold cleaning member is 1 mm or more, and the width of the cavity opening of the oval shape or quadrangular shape (rectangle, square, etc.) When the dimension is set to 4/5 or less, the above-described shrinkage is optimized, the mold cleaning sheet does not wrinkle or warp, and the cleaning property is improved, and the present invention has been achieved.

  In the mold cleaning sheet of the present invention, at least one surface of a sheet-like base material is formed in a longitudinal row composed of a plurality of block bodies in which strip-shaped mold cleaning members are cut at predetermined intervals in the longitudinal direction. The length is set within a range of 3 to 50 mm. For this reason, the shrinkage | contraction of the said metal mold | die cleaning member is disperse | distributed to each block body, becomes small, and can prevent a wrinkle and a curvature from generating in the metal mold | die cleaning sheet of this invention. In addition, since a gap is formed between the mold cleaning members of the block body in the column of the mold cleaning members, the gap is also between the mold cleaning members adjacent in the width direction of the mold cleaning member. It can be used as a gap for releasing air when cleaning the mold together with a gap between them (conventional gap), and the gap for releasing air increases. In addition, the gap between the block bodies in the column composed of the plurality of block bodies is set to a dimension of 0.1 mm or more and less than the width of the mold cleaning member, and the width direction of the mold cleaning member The clearance between the adjacent mold cleaning members is set to a dimension that is 1/2 or more of the width of the mold cleaning member and less than the width of the mold cleaning member. In combination with the fact that the wrinkles and warpage do not occur, the filling property of the mold cleaning member into the cavity is improved and the cleaning property is improved. Further, the width of the mold cleaning member is set to 1 mm or more and 4/5 or less of the lateral width of the oval or rectangular cavity opening, so that the cavity opening is small. Since the mold cleaning member partially closes the opening, the air releasing property in the cavity is excellent, and the filling property (cleaning property) of the mold cleaning member into the cavity is excellent.

  In particular, when the sheet-like base material is a fabric, the surface of the sheet-like base material becomes rough, so that the anchor effect of the mold cleaning member is improved. The adhesion with the cleaning member can be strengthened.

  In particular, when the fabric is a woven fabric or a nonwoven fabric using long fibers, the surface roughness of the sheet-like substrate (fabric) is appropriate, and the anchor effect of the mold cleaning member is appropriate. Can be

  Furthermore, when the non-woven fabric is a spunbonded non-woven fabric, the tensile strength is relatively non-directional, and the stress applied during heat forming is easily absorbed and relaxed, so that sheet breakage does not easily occur during heat forming. In addition, since the sheet is not broken during the peeling (demolding) from the mold, the peeling (demolding) operation is simplified.

  In addition, even when the sheet-like base material is embossed, the surface of the sheet-like base material becomes rough, so that the anchor effect of the mold cleaning member is improved. Adhesion with the mold cleaning member can be strengthened.

It is a perspective view showing typically a 1st embodiment of a metallic mold cleaning sheet of the present invention. It is a perspective view which shows typically 2nd Embodiment of the metal mold | die cleaning sheet of this invention. It is a perspective view which shows typically 3rd Embodiment of the metal mold | die cleaning sheet of this invention. (A)-(e) is sectional drawing orthogonal to the longitudinal direction of a metal mold | die cleaning member which shows the modification of a metal mold | die cleaning member typically. (A)-(c) is sectional drawing along the longitudinal direction of a metal mold | die cleaning member which shows the modification of a metal mold | die cleaning member typically. It is a top view which shows typically the example of the arrangement | positioning pattern of a metal mold | die cleaning member. (A), (b) is a top view which shows typically the example of the arrangement | positioning pattern of a metal mold | die cleaning member. (A), (b) is a top view which shows typically the example of the arrangement | positioning pattern of a metal mold | die cleaning member. It is a top view which shows typically the example of the arrangement | positioning pattern of a metal mold | die cleaning member. (A), (b) is a top view which shows typically the example of the arrangement | positioning pattern of a metal mold | die cleaning member. (A), (b) is a top view which shows typically the example of the arrangement | positioning pattern of a metal mold | die cleaning member. (A)-(e) is sectional drawing orthogonal to the longitudinal direction of a mold cleaning member which shows typically the other modification of a mold cleaning member. (A)-(c) is sectional drawing along the longitudinal direction of a metal mold | die cleaning member which shows the other modification of a metal mold | die cleaning member typically. It is a perspective view which shows the conventional metal mold | die cleaning sheet typically.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a first embodiment of a mold cleaning sheet of the present invention. The mold cleaning sheet of this embodiment is a mold cleaning sheet used for cleaning a mold in which a cavity having an opening of an oval shape or a square shape (rectangle, square, etc.) is formed. A plurality of block-shaped mold cleaning members 2 made of an unvulcanized rubber-based composition or a thermosetting resin-based composition are regularly arranged vertically and horizontally with gaps a and b on one side. Yes. That is, the mold cleaning sheet is the above-described conventional mold cleaning sheet (see FIG. 14), the band-shaped mold cleaning member 2 is divided into a plurality of block bodies with a predetermined gap a in the longitudinal direction, A column composed of the plurality of block bodies is formed. In addition, the length (longitudinal dimension) Y of the mold cleaning member 2 of the block body is set within a range of 3 to 50 mm, and the blocks in the column formed of the mold cleaning members 2 of the plurality of block bodies are arranged. The gap a between the bodies is set to 0.1 mm or more and less than the width X of the mold cleaning member 2 and the gap b between the mold cleaning members 2 adjacent in the width direction of the mold cleaning member 2 is set. The mold cleaning member 2 is set to 1/2 or more of the width X of the mold cleaning member 2 and less than or equal to the width X of the mold cleaning member 2, and the width X of the mold cleaning member 2 is set to 1 mm or more and the oval shape or The width is set to 4/5 or less of the lateral width of the rectangular cavity opening (the shorter width of the oval shape or the rectangular shape). The feature of the present invention is that the mold cleaning member 2 is arranged in a pattern having such dimensions. In this embodiment, the block body has a cross-sectional shape perpendicular to the longitudinal direction formed entirely in a dome shape.

  That is, the mold cleaning sheet of this embodiment is divided into a plurality of block bodies by separating the belt-shaped mold cleaning member 2 with a predetermined gap a in the longitudinal direction as described above. 2, the shrinkage in the longitudinal direction (the column direction of the block bodies) is dispersed, and the shrinkage of the entire mold cleaning sheet is suppressed. This is more effective when the mold cleaning sheet is enlarged for the purpose of improving productivity. Furthermore, by setting the length Y of the block body within a range of 3 to 50 mm, wrinkles and warpage are prevented from occurring in the mold cleaning sheet. In addition, the preferable range of the length Y of the said block body exists in the range of 10-40 mm from a viewpoint of the prevention of the said wrinkle and curvature. The height H of the block body is usually set within a range of 1 to 5 mm.

  Further, in the mold cleaning sheet of this embodiment, in the gap b between the mold cleaning members 2 adjacent in the width direction of the mold cleaning member 2 in the conventional mold cleaning sheet (see FIG. 14). In addition, as described above, a gap a is also formed between adjacent block bodies in the longitudinal direction of the mold cleaning member 2. Further, by setting the gaps a and b within the above range, air bleeding when cleaning the mold is optimized. The combination of proper air venting and prevention of wrinkles and warpage makes it easier for the mold cleaning sheet to adhere to the mold surface of the mold, so that the cavity of the mold cleaning member 2 is filled. The cleaning performance is improved.

  Furthermore, in the mold cleaning sheet of this embodiment, by setting the width X of the mold cleaning member 2 to 1 mm or more and 4/5 or less of the lateral width of the oval or rectangular cavity opening, Even if the cavity opening is small, the mold cleaning member 2 partially closes the cavity opening so that air in the cavity can be easily removed. Thereby, the filling property (cleaning property) into the cavity of the mold cleaning member 2 is excellent. In addition, the preferable range of the width X of the block body is in the range of 2/5 to 4/5 of the lateral width of the oval or rectangular cavity opening from the viewpoint of the filling property. However, the width X of the mold cleaning member 2 does not exceed 50 mm from the viewpoint of reducing the shrinkage of the mold cleaning member 2.

  In the mold cleaning sheet of this embodiment, as described above, the gaps a and b between the adjacent mold cleaning members 2 are formed in a lattice shape, thereby facilitating cutting vertically and horizontally. According to the size of the mold, it can be cut into an appropriate size for use.

  More specifically, examples of the material for forming the sheet-like substrate 1 include paper (Japanese paper, western paper, synthetic paper, etc.), fabric (woven fabric, nonwoven fabric, knitted fabric, etc.), plastic (polyethylene terephthalate, polyimide, polyethylene). Naphthalate, polyamide, polypropylene, etc.). Moreover, the thing of the range of 0.05-1 mm is used for the thickness of the said sheet-like base material 1, for example. Among them, from the viewpoint of producing the anchor effect of the mold cleaning member 2 and strengthening the adhesion with the mold cleaning member 2, nonwoven fabric, embossed, roughened, perforated Of these, a porous material and the like are preferable. In particular, a woven fabric and a nonwoven fabric using long fibers are preferable from the viewpoint that the anchor effect is appropriate because the surface is an appropriate rough surface, and among the nonwoven fabrics, from the viewpoint of excellent fracture resistance. A spunbonded nonwoven fabric is preferred.

  The unvulcanized rubber-based composition or the thermosetting resin-based composition forming the mold cleaning member 2 is obtained by adding an inorganic filler such as silica powder or titanium oxide to the unvulcanized rubber or thermosetting resin. The blending ratio is about 40 to 50 parts by weight of silica powder and about 5 parts by weight of titanium oxide with respect to 100 parts by weight of the unvulcanized rubber or thermosetting resin. If necessary, other components are also mixed as appropriate.

  Examples of the unvulcanized rubber include natural rubber (NR), chloroprene rubber (CR), butadiene rubber (BR), nitrile rubber (NBR), ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM), and styrene. Examples include butadiene rubber (SBR), polyisoprene rubber (IR), butyl rubber (IIR), silicone rubber (Q), and fluorine rubber (FKM).

  As said thermosetting resin, a melamine resin etc. are mention | raise | lifted, for example.

  The color of the mold cleaning member 2 is not particularly limited, but is preferably a light color such as white or gray. The reason is that the dirt to be removed from the cavity of the mold is a dark color such as black, so it can be easily confirmed with the naked eye that the dirt has adhered to the mold cleaning member 2 after cleaning, This is because the cleaning status can be easily confirmed. In order to make the light color, a white pigment or the like is added to the unvulcanized rubber composition or the thermosetting resin composition.

  The mold cleaning sheet can be produced, for example, by first kneading the unvulcanized rubber composition or thermosetting resin composition with a continuous or batch kneader, and then the sheet-like substrate. 1 on one side. Next, it is pressed with a mold in which a recess corresponding to the arrangement pattern of the mold cleaning member 2 is formed. Thereby, the mold cleaning member 2 having the above arrangement pattern is integrally formed on one surface of the sheet-like substrate 1. And after demolding, it is wound up or cut into appropriate dimensions. In this way, the mold cleaning sheet can be produced.

  In the above embodiment, the mold cleaning member 2 is formed only on one side of the sheet-like substrate 1, but it may be formed on both sides of the sheet-like substrate 1 as shown in FIG. 2. Moreover, as shown in FIG. 3, the longitudinal direction of the mold cleaning member 2 of the block body may be different between the front surface and the back surface of the sheet-like substrate 1 (the difference is 90 ° in FIG. 3).

  In the above embodiment, the cross-sectional shape perpendicular to the longitudinal direction of the mold cleaning member 2 is formed into a dome shape as a whole. However, the cross-sectional shape may be other, for example, FIG. As shown in (a), the top part may be formed in a dome shape and the lower part thereof may be formed in a trapezoidal shape, or the top part may be formed in a dome shape as shown in FIG. It may be formed in a rectangular shape. Further, the cross-sectional shape may be a triangle as shown in FIG. 4 (c), a trapezoid as shown in FIG. 4 (d), or a semicircle as shown in FIG. 4 (e). Good.

  4 (a) to 4 (c) and 4 (e), the top of the mold cleaning member 2 is formed in a non-flat shape. Therefore, even if the opening of the cavity is small, the opening is small. As a result, the top of the mold cleaning member 2 can be easily blocked and the air in the cavity can be more easily removed. As a result, the filling property of the mold cleaning material is further improved, and the cleaning property in the cavity is further improved.

  Further, as shown in FIG. 5 (a), the cross-sectional shape along the longitudinal direction of the mold cleaning member 2 is rectangular (both end surfaces in the longitudinal direction are perpendicular to the sheet-like substrate 1, and the peripheral portions of the both end surfaces. 5 may be a trapezoid (a shape in which both end faces in the longitudinal direction are inclined and peripheral edges of the both end faces are formed in corners) as shown in FIG. 5B. However, as shown in FIG. 5C, a shape in which both end surfaces in the longitudinal direction are formed in a curved shape (a shape in which the peripheral portions of both end surfaces are also rounded) may be used. In the embodiment shown in FIGS. 1 to 3, the sectional shape of the mold cleaning member 2 along the longitudinal direction is as shown in FIG.

  4 (a), (c) to (e), and FIGS. 5 (b) and 5 (c), the side surface and both end surfaces of the mold cleaning member 2 are perpendicular to the surface of the sheet-like substrate 1. For those not formed, the width X, length Y and gaps a and b of the mold cleaning member 2 are measured at the base (bottom surface) of the mold cleaning member 2.

  Examples of the arrangement pattern of the mold cleaning member 2 include those shown in plan views in FIGS. 6 to 11 show the base (bottom surface) of the mold cleaning member 2. That is, the arrangement pattern may be a pattern in which squares are regularly arranged vertically and horizontally as shown in FIG. 6, or an oval shape (width X: length Y = as shown in FIG. 7A). 1:10) may be a pattern in which the longitudinal direction is vertically arranged vertically and horizontally, or, as shown in FIG. 7B, the oval shape is horizontally and vertically oriented with the longitudinal direction being transverse. It may be a regularly arranged pattern. Further, as shown in FIG. 8A, a pattern in which rectangles (width X: length Y = 1: 10) are regularly arranged vertically and horizontally with the longitudinal direction thereof being vertical may be used. As shown in b), the rectangle may be a pattern in which the longitudinal direction thereof is arranged horizontally and vertically and horizontally, or as shown in FIG. The pattern arrange | positioned so that the end of the rectangle shown to (a) may correspond may be sufficient. Further, the ratio of the width X and the length Y of the rectangles in FIGS. 8A and 8B may be 1: 5.5 as shown in FIGS. 10A and 10B. As shown to (a) and (b), it is good also as 1: 4. In the embodiment shown in FIGS. 1 to 3, the arrangement pattern of the base (bottom surface) of the mold cleaning member 2 is as shown in FIG.

  Moreover, in the said embodiment, although the sheet-like base material 1 was exposed from the part of the clearance gaps a and b between the adjacent metal mold | die cleaning members 2, the sheet-like base material of the part of the clearance gaps a and b was exposed. 1 (a) to 12 (e) [sectional views corresponding to FIGS. 4 (a) to 4 (e)] and FIGS. 13 (a) to 13 (c) [FIGS. 5 (a) to (c). As shown in FIG. 2], a thin film mold cleaning member 2 (a thin film 2a made of an unvulcanized rubber-based composition or a thermosetting resin-based composition that is a material for forming the mold cleaning member 2) It may be covered with. In that case, the thickness of the thin film 2 a is preferably the same as the thickness of the sheet-like substrate 1. By doing so, even if the thin film 2a is formed between the projecting mold cleaning members 2, the contraction of the mold cleaning sheet is not adversely affected, and the mold cleaning sheet is not wrinkled or warped. .

  Next, examples will be described together with comparative examples. However, the present invention is not limited to the examples.

[Fabric sheet]
As a sheet-like base material, a spunbond nonwoven fabric (Asahi Kasei Co., Ltd., ELTAS E01070) made of polyester long fibers was prepared. This nonwoven fabric had a tear strength of 8.5 N, a thickness of 0.35 mm, and a basis weight of 70 g / m ² .

[Mold cleaning member]
100 parts by weight of ethylene propylene rubber, 50 parts by weight of silica powder, 5 parts by weight of titanium oxide, 2 parts by weight of organic peroxide [n-butyl-4,4-bis (t-butylperoxy) valerate], imidazole {2, 10 parts by weight of 4-diamino-6- [2′-methylimidazolyl- (1 ′)] ethyl-s-triazine} and 5 parts by weight of montan wax were kneaded with a kneader to prepare a mold cleaning member.

[Examples 1-5, Comparative Examples 1-6]
The mold cleaning material was formed on both surfaces of the sheet-like substrate in a pattern in which block bodies were regularly arranged vertically and horizontally with a gap therebetween (see FIG. 2). The shape of the block body is shown in FIG. 1, and the dimensions of the block body and the gap are shown in Tables 1 and 2 below.

[Shrinkage rate of mold cleaning sheet]
Before and after producing the mold cleaning sheets of Examples 1 to 5 and Comparative Examples 1 to 6, the dimension of the sheet-like substrate corresponding to the longitudinal direction of the mold cleaning material was measured, and the shrinkage of the sheet-like substrate The rate was calculated. As a result, those with shrinkage of less than 1% were evaluated as ◎, those with 1-3% were evaluated as ○, and those exceeding 3% were evaluated as ×, and are shown in Tables 1 and 2 below. Comparative examples 2 and 4 were not evaluated because they were difficult to produce.

[Fillability]
The molds were cleaned using the mold cleaning sheets of Examples 1 to 5 and Comparative Examples 1 to 6. This mold is a transfer molding mold used for resin-sealing a semiconductor element. The mold includes an upper mold and a lower mold. Each mold surface (opposing surface) of these upper mold and lower mold. Is a rectangle of 24 mm × 91 mm. In addition, the shape of each cavity in the clamped state is a substantially rectangular parallelepiped shape (the cavity opening is an oval shape), and the dimensions are 5 mm × 5 mm × 2 mm (height) (the width of the cavity opening is 5 mm). Further, 16 cavities are formed, and 8 cavities are arranged in parallel in two rows. The interval between the two rows is 10 mm, and the interval between adjacent cavities in each row is 1 mm. The cleaning conditions were such that the mold clamping gap was 0.5 mm, the molding temperature was 175 ° C., and the molding time was 5 minutes. And the state of cleaning was confirmed visually. As a result, those that could be cleaned to every corner of the cavity were evaluated as ◯ as being excellent in fillability, and those that were not cleaned at the corner of the cavity were evaluated as × as being poor in fillability, and the following The results are shown in Tables 1 and 2. Comparative examples 2 and 4 were not evaluated because they were difficult to produce.

  From the results of Tables 1 and 2, it can be seen that the mold cleaning sheets of Examples 1 to 5 are superior to the mold cleaning sheets of Comparative Examples 1 to 6 in filling and cleaning properties.

  The mold cleaning sheet of the present invention can be used for cleaning the mold surface of a molding mold.

DESCRIPTION OF SYMBOLS 1 Sheet-like base material 2 Mold cleaning member X Width Y Length a, b Gap

Claims (5)

  A mold cleaning sheet used for cleaning a mold in which a cavity having an oval or rectangular opening is formed, and an unvulcanized rubber composition or a thermosetting material on at least one side of the sheet-like substrate A plurality of strip-shaped mold cleaning members made of a resin-based composition are arranged in parallel with a gap, and the strip-shaped mold cleaning members are cut at a predetermined interval in the longitudinal direction from a plurality of block bodies. And the length of the block bodies is set in a range of 3 to 50 mm, and the gap between the block bodies is 0.1 mm or more in the column composed of the plurality of block bodies. The gap between the mold cleaning member that is set to a dimension equal to or smaller than the width of the mold cleaning member and that is adjacent in the width direction of the mold cleaning member is The width of the mold cleaning member is set to ½ or more of the width of the mold cleaning member, and the width of the mold cleaning member is 1 mm or more, and the oval shape or A mold cleaning sheet characterized in that it is set to a dimension of 4/5 or less of the lateral width of the rectangular cavity opening.   The mold cleaning sheet according to claim 1, wherein the sheet-like substrate is a fabric.   The mold cleaning sheet according to claim 2, wherein the fabric is a woven fabric or a nonwoven fabric using long fibers.   The mold cleaning sheet according to claim 3, wherein the nonwoven fabric is a spunbond nonwoven fabric.   The mold cleaning sheet according to any one of claims 1 to 4, wherein the sheet-like substrate is embossed.

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