A polishing pad with high porosity and high modulus polishing layer and a method of making the same

Abstract

The application discloses a polishing pad with a high-porosity high-modulus polishing layer and a preparation method thereof, and belongs to the technical field of polishing pads. The polishing pad comprises a base layer and a polishing layer. The polishing layer is arranged on the base layer and is adhesively connected to the base layer through EVA hot melt adhesive. The EVA hot melt adhesive comprises the following raw materials in mass fractions: 47-50 parts of EVA resin, 35-36 parts of tackifier, 8-12 parts of paraffin, 3-7 parts of filler and 0.5-2 parts of antioxidant. The application solves the problem that the existing polishing pad has poor wear resistance and low storage modulus during use, thereby leading to low polishing pad removal rate and poor flatness and reducing the use effect of the polishing pad. The polishing layer prepared by the application has the characteristics of high porosity and high modulus, the wear resistance and the storage modulus of the polishing pad can be improved, the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polishing pads, in particular to a polishing pad with a polishing layer of high porosity and high modulus and a preparation method thereof. BACKGROUND

[0002] A polishing pad, also known as a polishing skin, a polishing cloth or a polishing sheet, is an important auxiliary material in chemical mechanical polishing that determines the surface quality. It can be divided into abrasive polishing pads and non-abrasive polishing pads according to whether it contains abrasive. It can be divided into polyurethane polishing pads, non-woven polishing pads and composite polishing pads according to different materials. It can be roughly divided into planar type, grid type and spiral line type according to different surface structures.

[0003] A polishing pad and a preparation method thereof are disclosed in Chinese Patent No. CN111216037B. The abrasive layer of the polishing pad is composed of the following components in mass percentage: aggregate abrasive 10-22%, coupling agent 1-5%, resin binder 45-65%, calcium carbonate 10-20%, cerium oxide 10-20%, fumed silica 1-5%, sodium bicarbonate 1-5%, and fine fiber 1-3%. In the abrasive layer of the polishing pad, sodium bicarbonate, as a pore former, can decompose during the curing process to produce tiny pores, which is beneficial to chip removal during polishing and to the stability of polishing efficiency. Cerium oxide, calcium carbonate, fumed silica, nano-alumina, etc. act as filling materials to ensure the strength of the working layer. In addition, cerium oxide acts as auxiliary abrasive, fumed silica can prevent sedimentation to make the slurry composition uniform, and fine fiber plays a role of skeleton support when the abrasive layer is formed. However, the polishing pad of the patent has the following defects during use:

[0004] The existing polishing pad has poor wear resistance and low storage modulus during use, resulting in low polishing pad removal rate and poor flatness, which reduces the use effect of the polishing pad. SUMMARY

[0005] The present application provides a polishing pad with a polishing layer of high porosity and high modulus and a preparation method thereof, which can improve the wear resistance and storage modulus of the polishing pad, increase the polishing pad removal rate and flatness, and improve the use effect of the polishing pad, thereby solving the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The polishing pad of high porosity and high modulus polishing layer comprises a base layer and a polishing layer, the polishing layer is arranged on the base layer, the polishing layer is adhered on the base layer by EVA hot melt adhesive, and the EVA hot melt adhesive comprises the following raw materials in mass fraction: EVA resin 47-50 parts, tackifier 35-36 parts, paraffin 8-12 parts, filler 3-7 parts and antioxidant 0.5-2 parts.

[0008] Preferably, the base layer comprises a substrate layer and a buffer layer, the substrate layer is adhered on the buffer layer by EVA hot melt adhesive, and the buffer layer is adhered on the polishing layer by EVA hot melt adhesive.

[0009] Preferably, the substrate layer takes polypropylene particles and polyurethane particles as raw materials, is heated and melted by a screw extruder, is extruded into melt, is extruded from the spinneret orifices of the die head in opposite directions, is blown by hot air streams on both sides of the spinneret orifices, is stretched into the warp ultra-fine fibers, and is formed into the substrate layer by self-bonding, wherein the mass fraction ratio of the polypropylene particles and the polyurethane particles is 2:1.

[0010] Preferably, the buffer layer takes polyurethane foam and polyethylene foam as raw materials, is stirred, mixed, plasticized and compacted in a cylinder by an extruder with the placement of an extrusion screw, is extruded into a product with a certain shape from a die head, and is strongly extruded and stretched under the action of friction by a calender to form a calendered product with uniform thickness, and is formed into the buffer layer by shearing processing.

[0011] Preferably, the polishing layer comprises a polishing bottom layer and a polishing surface layer, the polishing surface layer is adhered on the polishing bottom layer by EVA hot melt adhesive, and the polishing bottom layer is adhered on the buffer layer by EVA hot melt adhesive, wherein the polishing surface layer comprises the following raw materials in mass fraction: sub-micron cerium oxide 50-70 parts, zirconium oxide 2-5 parts, chromium oxide 5-10 parts, rare earth 10-15 parts, silicon dioxide 5-10 parts and the balance of cobalt.

[0012] Preferably, the polishing bottom layer is provided with longitudinal polishing strips and transverse polishing strips, the longitudinal polishing strips and the transverse polishing strips are connected, and the longitudinal polishing strips and the transverse polishing strips are integrally connected on the polishing bottom layer.

[0013] Preferably, the longitudinal polishing strips and the transverse polishing strips are distributed in the polishing bottom layer in a crisscross manner, and polishing pores are formed between the longitudinal polishing strips and the transverse polishing strips.

[0014] Preferably, the polishing bottom layer takes thermoplastic polyurethane elastomer as raw material, is stirred, mixed, plasticized, compacted, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and is formed into the polishing bottom layer by shearing processing.

[0015] Preferably, the longitudinal polishing strip and the transverse polishing strip are made of thermoplastic polyurethane elastomer and polypropylene, and are stirred, mixed, plasticized, compressed, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and are processed by shearing to form the longitudinal polishing strip and the transverse polishing strip, wherein the thermoplastic polyurethane elastomer and the polypropylene include raw materials in the following mass fractions: 20-36 parts of thermoplastic polyurethane elastomer and 15-32 parts of polypropylene.

[0016] According to another aspect of the present application, a method for preparing the polishing pad with high porosity and high modulus polishing layer is provided, and the method comprises the following steps:

[0017] S1, preparing a base layer:

[0018] The polypropylene granules and the polyurethane granules with a mass ratio of 2:1 are added into a screw extruder, are heated and melted by the screw extruder, are extruded into melts, are extruded from the spinneret holes of the spinneret in opposite directions, are subjected to the hot air blowing from both sides of the spinneret holes, are stretched into the warp ultra-fine fibers, and are formed into the base layer through self-bonding;

[0019] The polyurethane foam and the polyethylene foam with a mass ratio of 1:0.8-1.2 are added into an extruder, are stirred, mixed, plasticized and compressed in the cylinder of the extruder by the placement of the extrusion screw, are extruded from the die of the extruder into a product with a certain shape, and are subjected to strong extrusion and stretching under the friction force of the calender to form a calendered product with uniform thickness, and are processed by shearing to form the buffer layer;

[0020] The prepared buffer layer is adhered to the prepared base layer by EVA hot melt adhesive, and after lamination, the base layer is formed;

[0021] S2, preparing a polishing layer:

[0022] The thermoplastic polyurethane elastomer is added into an extrusion molding machine, is stirred, mixed, plasticized, compressed, extruded and stretched by the extrusion molding machine to form a calendered product with uniform thickness, and is processed by shearing to form the polishing bottom layer;

[0023] A certain mass fraction of thermoplastic polyurethane elastomer and polypropylene is added into an extrusion molding machine, is stirred, mixed, plasticized, compressed, extruded and stretched by the extrusion molding machine to form a calendered product with uniform thickness, and is processed by shearing to form the longitudinal polishing strip and the transverse polishing strip;

[0024] The sub-micron cerium oxide, zirconium oxide, chromium oxide, rare earth, silicon dioxide and cobalt are added into a mixing grinder in proportion, are fully mixed and ground, are formed into the polishing surface layer after die molding;

[0025] The longitudinal polishing strips and the transverse polishing strips are processed in the polishing bottom layer, and polishing gaps are formed between the longitudinal polishing strips and the transverse polishing strips, and the polishing surface layer is adhered to the polishing bottom layer through EVA hot melt adhesive to form the polishing layer.

[0026] S3, preparing the polishing pad:

[0027] The polishing layer is adhered to the base layer through EVA hot melt adhesive, and after lamination, the polishing pad is formed.

[0028] Compared with the prior art, the polishing pad with the polishing layer with high porosity and high modulus and the preparation method have the following beneficial effects:

[0029] The polishing pad with the polishing layer with high porosity and high modulus and the preparation method have the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a front view of the polishing pad with the polishing layer with high porosity and high modulus of the present application.

[0031] Figure 2 It is a front view of the base layer of the present application.

[0032] Figure 3 It is a front view of the polishing layer of the present application.

[0033] Figure 4 It is an enlarged view of A in the polishing pad with the polishing layer with high porosity and high modulus of the present application. Figure 3

[0034] In the figure: 1, base layer; 11, base layer; 12, buffer layer; 2, polishing layer; 21, polishing bottom layer; 211, longitudinal polishing strip; 212, transverse polishing strip; 213, polishing gap; 22, polishing surface layer. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] ​In order to solve the problem of poor wear resistance and low storage modulus of the existing polishing pad in use, which leads to low polishing pad removal rate and poor flatness, and reduces the use effect of the polishing pad, please refer to Figures 1-4 The embodiment provides the following technical scheme:

[0037] Embodiment one

[0038] A polishing pad with high porosity and high modulus polishing layer, comprising a base layer 1 and a polishing layer 2, the polishing layer 2 is arranged on the base layer 1, and the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, the EVA hot melt adhesive comprises the following raw materials in mass fraction: EVA resin 47-50 parts, tackifier 35-36 parts, paraffin 8-12 parts, filler 3-7 parts and antioxidant 0.5-2 parts.

[0039] Specifically, the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, so that the prepared polishing pad has the characteristics of high porosity and high modulus, the wear resistance and the storage modulus of the polishing pad can be improved, the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0040] The base layer 1 comprises a substrate layer 11 and a buffer layer 12, the substrate layer 11 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the buffer layer 12 is adhered to the polishing layer 2 by EVA hot melt adhesive.

[0041] The substrate layer 11 is prepared by taking polypropylene particles and polyurethane particles as raw materials, heating and melting by a screw extruder, extruding into melt, and extruding the two melts from the spinneret holes in opposite directions, so that the melt is stretched into a longitudinal ultra-fine fiber under the blowing of hot air on both sides of the spinneret hole, and the substrate layer 11 is formed by self-bonding, wherein the mass fraction ratio of the polypropylene particles and the polyurethane particles is 2:1.

[0042] The buffer layer 12 is prepared by taking polyurethane foam and polyethylene foam as raw materials, stirring, mixing, plasticizing and compacting in the cylinder by an extruder with the placement of an extrusion screw, extruding a product with a certain shape from the die head, and the extruded product with a certain shape is subjected to strong extrusion and extension under the action of friction by a calender, so that a calendered product with uniform thickness is formed, and the buffer layer 12 is formed by shearing processing, wherein the mass fraction ratio of the polyurethane foam and the polyethylene foam is 1:0.8-1.2.

[0043] The polishing layer 2 comprises a polishing bottom layer 21 and a polishing surface layer 22, the polishing surface layer 22 is adhered to the polishing bottom layer 21 by EVA hot melt adhesive, and the polishing bottom layer 21 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the polishing surface layer 22 comprises the following raw materials in mass fraction: 50-70 parts of submicron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide and the balance of cobalt.

[0044] The polishing base layer 21 is provided with longitudinal polishing strips 211 and transverse polishing strips 212, the longitudinal polishing strips 211 and the transverse polishing strips 212 are connected, and the longitudinal polishing strips 211 and the transverse polishing strips 212 are integrally connected on the polishing base layer 21.

[0045] The longitudinal polishing strips 211 and the transverse polishing strips 212 are distributed in the polishing base layer 21 in a longitudinal and transverse staggered manner, and polishing apertures 213 are formed between the longitudinal polishing strips 211 and the transverse polishing strips 212.

[0046] The polishing base layer 21 is made of thermoplastic polyurethane elastomer, and is stirred, mixed, plasticized, compressed, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and is subjected to shearing processing to form the polishing base layer 21.

[0047] The longitudinal polishing strips 211 and the transverse polishing strips 212 are made of thermoplastic polyurethane elastomer and polypropylene, and are stirred, mixed, plasticized, compressed, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and are subjected to shearing processing to form the longitudinal polishing strips 211 and the transverse polishing strips 212, wherein the thermoplastic polyurethane elastomer and the polypropylene include the following raw materials in mass fraction: 20 parts of thermoplastic polyurethane elastomer and 15 parts of polypropylene.

[0048] Specifically, the thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber, is a (AB)n type block linear polymer, A is a polyester or polyether with a high molecular weight of 1000-6000, B is a diol containing 2-12 straight chain carbon atoms, and the chemical structure between AB segments is diisocyanate; the thermoplastic polyurethane rubber is crosslinked by intermolecular hydrogen bonds or slightly crosslinked between macromolecular chains, and the two crosslinked structures have reversibility as the temperature rises or falls, the intermolecular force is weakened in the molten state or solution state, and after cooling or solvent evaporation, there is strong intermolecular force to connect together, restoring the original solid properties.

[0049] The thermoplastic polyurethane elastomer has excellent comprehensive properties such as high strength, high toughness, wear resistance, oil resistance, good processing performance, and its molecules are basically linear, with no or very little chemical crosslinking, there are many physical crosslinking of hydrogen bonds between linear polyurethane molecular chains, and the hydrogen bonds play a strengthening role on the form, thereby giving many excellent properties such as high modulus, high strength, excellent wear resistance, chemical resistance, hydrolysis resistance, high and low temperature resistance and mold resistance.

[0050] Specifically, polypropylene is abbreviated as PP, which is a polymer formed by polyaddition reaction of propylene, and is a kind of excellent thermoplastic synthetic resin with excellent properties such as chemical resistance, heat resistance, electrical insulation, high strength mechanical properties and good high wear resistance processing performance.

[0051] Specifically, the thermoplastic polyurethane elastomer and the polypropylene are used to prepare the longitudinal polishing strips 211 and the transverse polishing strips 212, and the longitudinal polishing strips 211 and the transverse polishing strips 212 are distributed in the polishing bottom layer 21 in a longitudinal and transverse staggered manner, so that polishing apertures 213 are formed between the longitudinal polishing strips 211 and the transverse polishing strips 212, the polishing layer 2 prepared has the characteristics of high porosity and high modulus, and the wear resistance and the storage modulus of the polishing pad can be improved, so that the polishing pad has a high removal rate and a good flatness, and the use effect of the polishing pad is improved.

[0052] In order to better show the preparation process of the polishing pad with the polishing layer of high porosity and high modulus, the present embodiment proposes a preparation method of the polishing pad with the polishing layer of high porosity and high modulus, comprising the following steps:

[0053] S1, preparing a base layer 1:

[0054] The polypropylene granules and the polyurethane granules with a mass ratio of 2:1 are added into a screw extruder, heated and melted by the screw extruder, and extruded into melts, which are extruded from the spinneret holes of the die head in opposite directions, subjected to the blowing of hot air streams on both sides of the spinneret holes, stretched into longitudinal ultra-fine fibers, and formed into the base layer 11 through self-bonding;

[0055] The polyurethane foam and the polyethylene foam with a mass ratio of 1:0.8-1.2 are added into an extruder, stirred, mixed, plasticized and compacted in the cylinder of the extruder by the placement of the extrusion screw, and extruded into a product with a certain shape from the die head, and the product with a certain shape is subjected to strong extrusion and extension under the action of friction by a calender, and formed into a calendered product with uniform thickness, which is subjected to shearing processing to form the buffer layer 12;

[0056] The prepared buffer layer 12 is adhered to the prepared base layer 11 by EVA hot melt adhesive, and after lamination, the base layer 1 is formed;

[0057] S2, preparing a polishing layer 2:

[0058] The thermoplastic polyurethane elastomer is added into an extrusion molding machine, and stirred, mixed, plasticized, compacted, extruded and extended by the extrusion molding machine to form a calendered product with uniform thickness, which is subjected to shearing processing to form the polishing bottom layer 21;

[0059] A certain mass fraction of the thermoplastic polyurethane elastomer and the polypropylene is added into an extrusion molding machine, and stirred, mixed, plasticized, compacted, extruded and extended by the extrusion molding machine to form a calendered product with uniform thickness, which is subjected to shearing processing to form the longitudinal polishing strips 211 and the transverse polishing strips 212;

[0060] Submicron cerium oxide, zirconium oxide, chromium oxide, rare earth, silicon dioxide and cobalt are added into a mixing grinder in proportion, mixed and ground, and then molded into the polishing surface layer 22;

[0061] The longitudinal polishing strips 211 and the transverse polishing strips 212 are processed in the polishing base layer 21, and the polishing apertures 213 are formed between the longitudinal polishing strips 211 and the transverse polishing strips 212, and the polishing surface layer 22 is adhered to the polishing base layer 21 by EVA hot melt adhesive to form the polishing layer 2.

[0062] S3, preparing the polishing pad:

[0063] The polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, and after laminating, the polishing pad is formed.

[0064] Example two

[0065] A polishing pad with high porosity and high modulus polishing layer comprises a base layer 1 and a polishing layer 2, and the polishing layer 2 is arranged on the base layer 1 and adhered to the base layer 1 by EVA hot melt adhesive. The EVA hot melt adhesive comprises the following raw materials in mass fraction: EVA resin 47-50 parts, tackifier 35-36 parts, paraffin 8-12 parts, filler 3-7 parts and antioxidant 0.5-2 parts.

[0066] Specifically, the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, so that the prepared polishing pad has the characteristics of high porosity and high modulus, and the wear resistance and storage modulus of the polishing pad are improved, the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0067] The base layer 1 comprises a substrate layer 11 and a buffer layer 12, and the substrate layer 11 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the buffer layer 12 is adhered to the polishing layer 2 by EVA hot melt adhesive.

[0068] The substrate layer 11 is prepared by taking polypropylene particles and polyurethane particles as raw materials, heating and melting by a screw extruder, extruding into melt, and extruding the two melts from the spinneret holes in opposite directions, and the melt is stretched into longitudinal ultra-fine fibers under the blowing of hot air on both sides of the spinneret holes, and the substrate layer 11 is formed by self-bonding. The mass fraction ratio of the polypropylene particles and the polyurethane particles is 2:1.

[0069] The buffer layer 12 is prepared by taking polyurethane foam and polyethylene foam as raw materials, stirring, mixing, plasticizing and compacting in the cylinder by the extruder through the placement of the extrusion screw, and extruding products of a certain shape from the die head, and the extruded products of a certain shape are strongly extruded and stretched under the action of friction by a calender, and a calendered product with uniform thickness is formed, and the buffer layer 12 is formed by shearing processing. The mass fraction ratio of the polyurethane foam and the polyethylene foam is 1:0.8-1.2.

[0070] The polishing layer 2 comprises a polishing base layer 21 and a polishing surface layer 22, the polishing surface layer 22 is adhered to the polishing base layer 21 by EVA hot melt adhesive, the polishing base layer 21 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the polishing surface layer 22 comprises the following raw materials in mass fraction: 50-70 parts of sub-micron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide, and the balance of cobalt.

[0071] The polishing base layer 21 is provided with longitudinal polishing strips 211 and transverse polishing strips 212, the longitudinal polishing strips 211 and the transverse polishing strips 212 are connected, and the longitudinal polishing strips 211 and the transverse polishing strips 212 are integrally connected to the polishing base layer 21.

[0072] The longitudinal polishing strips 211 and the transverse polishing strips 212 are distributed in the polishing base layer 21 in a longitudinal and transverse staggered manner, and polishing apertures 213 are formed between the longitudinal polishing strips 211 and the transverse polishing strips 212.

[0073] The polishing base layer 21 is formed by using thermoplastic polyurethane elastomer as raw material, stirring, mixing, plasticizing, compacting, extruding and extending by an extrusion molding machine, forming a calendered product with uniform thickness, and shearing processing to form the polishing base layer 21.

[0074] The longitudinal polishing strips 211 and the transverse polishing strips 212 are formed by using thermoplastic polyurethane elastomer and polypropylene as raw material, stirring, mixing, plasticizing, compacting, extruding and extending by an extrusion molding machine, forming a calendered product with uniform thickness, and shearing processing to form the longitudinal polishing strips 211 and the transverse polishing strips 212, wherein the thermoplastic polyurethane elastomer and the polypropylene comprise the following raw materials in mass fraction: 20 parts of thermoplastic polyurethane elastomer and 32 parts of polypropylene.

[0075] Specifically, the thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber, is a (AB)n type block linear polymer, A is a polyester or polyether with a high molecular weight of 1000-6000, B is a diol containing 2-12 straight chain carbon atoms, and the chemical structure between AB segments is diisocyanate; the thermoplastic polyurethane rubber is crosslinked by intermolecular hydrogen bond or slightly crosslinked between macromolecular chains, and the two kinds of crosslinked structures have reversibility with the increase or decrease of temperature, the intermolecular force is weakened in the molten state or solution state, and after cooling or solvent evaporation, there is strong intermolecular force to connect together, restoring the original solid properties.

[0076] Thermoplastic polyurethane elastomer has high strength, high toughness, wear resistance, oil resistance and other excellent comprehensive performance, good processing performance, its molecule is basically linear, has no or little chemical crosslinking, there are many physical crosslinking of hydrogen bonds between linear polyurethane molecular chains, hydrogen bonds play a strengthening role on its form, thereby giving many excellent properties, such as high modulus, high strength, excellent wear resistance, chemical resistance, hydrolysis resistance, high and low temperature resistance and mold resistance.

[0077] Specifically, polypropylene is abbreviated as PP, which is a polymer formed by polypropylene through polyaddition reaction, and is a kind of excellent thermoplastic synthetic resin with excellent performance, chemical resistance, heat resistance, electrical insulation, high strength mechanical properties and good high wear resistance and processing performance.

[0078] Specifically, the longitudinal polishing strip 211 and the transverse polishing strip 212 are prepared by using thermoplastic polyurethane elastomer and polypropylene, and the longitudinal polishing strip 211 and the transverse polishing strip 212 are distributed in the polishing bottom layer 21 in a longitudinal and transverse staggered manner, so that polishing apertures 213 are formed between the longitudinal polishing strip 211 and the transverse polishing strip 212. The polishing layer 2 prepared has high porosity and high modulus characteristics, and the wear resistance and storage modulus of the polishing pad can be improved, so that the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0079] The polishing pad is prepared by using the same preparation method as in Example 1, and the difference between Example 2 and Example 1 is that the mass fraction of polypropylene in Example 2 is increased.

[0080] Example Three

[0081] A polishing pad with high porosity and high modulus polishing layer, comprising a base layer 1 and a polishing layer 2, the polishing layer 2 is arranged on the base layer 1, and the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive. The EVA hot melt adhesive comprises the following raw materials in mass fraction: EVA resin 47-50 parts, tackifier 35-36 parts, paraffin 8-12 parts, filler 3-7 parts and antioxidant 0.5-2 parts.

[0082] Specifically, the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, so that the polishing pad prepared has high porosity and high modulus characteristics, and the wear resistance and storage modulus of the polishing pad can be improved, so that the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0083] The base layer 1 comprises a base layer 11 and a buffer layer 12, the base layer 11 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the buffer layer 12 is adhered to the polishing layer 2 by EVA hot melt adhesive.

[0084] The base layer 11 is made of polypropylene particles and polyurethane particles as raw materials, heated and melted by a screw extruder, extruded into a melt, and extruded from the spinneret orifice of the die head, blown by the hot air flow on both sides of the spinneret orifice, and stretched into a longitudinal ultra-fine fiber by self-bonding to form the base layer 11, wherein the mass ratio of the polypropylene particles and the polyurethane particles is 2:1.

[0085] The buffer layer 12 is made of polyurethane foam and polyethylene foam as raw materials, stirred, mixed, plasticized and compacted in the cylinder by the extruder, extruded from the die head, and the extruded product is subjected to strong extrusion and extension under the action of friction by the calendering machine to form a calendering product with uniform thickness, and the buffer layer 12 is formed by shearing processing, wherein the mass ratio of the polyurethane foam and the polyethylene foam is 1:0.8-1.2.

[0086] The polishing layer 2 includes a polishing bottom layer 21 and a polishing surface layer 22, the polishing surface layer 22 is adhered to the polishing bottom layer 21 by EVA hot melt adhesive, the polishing bottom layer 21 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the polishing surface layer 22 includes the following raw materials in the following mass ratio: 50-70 parts of sub-micron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide, and the balance of cobalt.

[0087] The polishing bottom layer 21 is provided with longitudinal polishing strips 211 and transverse polishing strips 212, the longitudinal polishing strips 211 and the transverse polishing strips 212 are connected, and the longitudinal polishing strips 211 and the transverse polishing strips 212 are integrally connected to the polishing bottom layer 21.

[0088] The longitudinal polishing strips 211 and the transverse polishing strips 212 are distributed longitudinally and transversely in the polishing bottom layer 21, and the polishing apertures 213 are formed between the longitudinal polishing strips 211 and the transverse polishing strips 212.

[0089] The polishing bottom layer 21 is made of thermoplastic polyurethane elastomer as raw material, stirred, mixed, plasticized, compacted, extruded and extended by an extrusion molding machine to form a calendering product with uniform thickness, and the polishing bottom layer 21 is formed by shearing processing.

[0090] The longitudinal polishing strips 211 and the transverse polishing strips 212 are made of thermoplastic polyurethane elastomer and polypropylene as raw materials, stirred, mixed, plasticized, compacted, extruded and extended by an extrusion molding machine to form a calendering product with uniform thickness, and the longitudinal polishing strips 211 and the transverse polishing strips 212 are formed by shearing processing, wherein the thermoplastic polyurethane elastomer and the polypropylene include the following raw materials in the following mass ratio: 36 parts of thermoplastic polyurethane elastomer and 15 parts of polypropylene.

[0091] Specifically, the thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber, is a (AB)n type block linear polymer, A is a polyester or polyether with a high molecular weight of 1000-6000, B is a diol containing 2-12 linear carbon atoms, and the chemical structure between AB segments is diisocyanate; the thermoplastic polyurethane rubber is cross-linked by intermolecular hydrogen bonds or slightly cross-linked between macromolecular chains, and the two cross-linked structures are reversible with the increase or decrease of temperature, and the intermolecular force is weakened in the molten state or solution state, and after cooling or solvent evaporation, there is strong intermolecular force to connect together, restoring the original solid properties.

[0092] The thermoplastic polyurethane elastomer has high strength, high toughness, wear resistance, oil resistance and other excellent comprehensive properties, good processing performance, and its molecules are basically linear, without or with little chemical cross-linking, and there are many physical cross-linking of hydrogen bonds between linear polyurethane molecular chains, and the hydrogen bonds play a strengthening role on the form, thereby giving many excellent properties, such as high modulus, high strength, excellent wear resistance, chemical resistance, hydrolysis resistance, high and low temperature resistance and mold resistance.

[0093] Specifically, polypropylene is abbreviated as PP, which is a polymer formed by polyaddition of propylene, and is a kind of excellent thermoplastic synthetic resin with good properties, such as chemical resistance, heat resistance, electrical insulation, high strength mechanical properties and good high wear resistance processing performance.

[0094] Specifically, the thermoplastic polyurethane elastomer and polypropylene are used to prepare the longitudinal polishing strip 211 and the transverse polishing strip 212, and the longitudinal polishing strip 211 and the transverse polishing strip 212 are distributed in the polishing bottom layer 21 in a longitudinal and transverse staggered manner, so that polishing apertures 213 are formed between the longitudinal polishing strip 211 and the transverse polishing strip 212, which can make the prepared polishing layer 2 have high porosity and high modulus characteristics, and can improve the wear resistance and storage modulus of the polishing pad, so that the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0095] The polishing pad is prepared by the same preparation method as in Example One, and the difference from Example One is that the mass fraction of the thermoplastic polyurethane elastomer is increased in Example Three.

[0096] Comparative Example One

[0097] A polishing pad with high porosity and high modulus polishing layer, comprising a base layer 1 and a polishing layer 2, the polishing layer 2 is arranged on the base layer 1, and the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, the EVA hot melt adhesive comprises the following raw materials in mass fraction: EVA resin 47-50 parts, tackifier 35-36 parts, paraffin 8-12 parts, filler 3-7 parts and antioxidant 0.5-2 parts.

[0098] Specifically, the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, so that the prepared polishing pad has high porosity and high modulus characteristics, and the wear resistance and storage modulus of the polishing pad are improved, the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0099] The base layer 1 comprises a substrate layer 11 and a buffer layer 12, the substrate layer 11 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the buffer layer 12 is adhered to the polishing layer 2 by EVA hot melt adhesive.

[0100] The substrate layer 11 is prepared from polypropylene particles and polyurethane particles as raw materials, heated and melted by a screw extruder, extruded into a melt, and the two melts are respectively extruded from the spinneret holes of the die head, subjected to hot air blowing from both sides of the spinneret hole, and the melt is stretched into a longitudinal ultra-fine fiber, and the substrate layer 11 is formed by self-bonding, wherein the mass fraction ratio of the polypropylene particles and the polyurethane particles is 2:1.

[0101] The buffer layer 12 is prepared from polyurethane foam and polyethylene foam as raw materials, stirred, mixed, plasticized and compacted in the cylinder by an extruder with the placement of the extrusion screw, and a product with a certain shape is extruded from the die head, and the extruded product with a certain shape is subjected to strong extrusion and extension under the action of friction by a calender, and a calendered product with uniform thickness is formed, and the buffer layer 12 is formed by shearing processing.

[0102] The polishing layer 2 comprises a polishing bottom layer 21 and a polishing surface layer 22, the polishing surface layer 22 is adhered to the polishing bottom layer 21 by EVA hot melt adhesive, and the polishing bottom layer 21 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the polishing surface layer 22 comprises the following raw materials in mass fraction: 50-70 parts of submicron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide, and the balance of cobalt.

[0103] The polishing bottom layer 21 is provided with a longitudinal polishing strip 211, and the longitudinal polishing strip 211 is integrally connected to the polishing bottom layer 21.

[0104] The polishing bottom layer 21 is prepared from thermoplastic polyurethane elastomer as raw material, and is stirred, mixed, plasticized, compacted, extruded and extended by an extrusion molding machine to form a calendered product with uniform thickness, and the polishing bottom layer 21 is formed by shearing processing.

[0105] The longitudinal polishing strip 211 is prepared from thermoplastic polyurethane elastomer and polypropylene as raw materials, and is stirred, mixed, plasticized, compacted, extruded and extended by an extrusion molding machine to form a calendered product with uniform thickness, and the longitudinal polishing strip 211 is formed by shearing processing, wherein the thermoplastic polyurethane elastomer and the polypropylene comprise the following raw materials in mass fraction: 20 parts of thermoplastic polyurethane elastomer and 15 parts of polypropylene.

[0106] Comparative Example 1 is the same as Example 1 except that the transverse polishing strip 212 structure is omitted.

[0107] Comparative Example 2

[0108] A polishing pad with a high porosity and high modulus polishing layer, comprising a base layer 1 and a polishing layer 2, the polishing layer 2 is arranged on the base layer 1 and is adhered to the base layer 1 by EVA hot melt adhesive, the EVA hot melt adhesive comprises the following raw materials in mass fraction: EVA resin 47-50 parts, tackifier 35-36 parts, paraffin 8-12 parts, filler 3-7 parts and antioxidant 0.5-2 parts.

[0109] Specifically, the polishing layer 2 is adhered to the base layer 1 by EVA hot melt adhesive, which can make the prepared polishing pad have the characteristics of high porosity and high modulus, and can improve the wear resistance and storage modulus of the polishing pad, so that the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0110] The base layer 1 comprises a substrate layer 11 and a buffer layer 12, the substrate layer 11 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the buffer layer 12 is adhered to the polishing layer 2 by EVA hot melt adhesive.

[0111] The substrate layer 11 is made of polypropylene particles and polyurethane particles as raw materials, heated and melted by a screw extruder, extruded into a melt, and the two melts are respectively extruded from the spinneret holes of the die, subjected to hot air blowing from both sides of the spinneret holes, and stretched into longitudinal ultra-fine fibers by self-bonding to form the substrate layer 11, wherein the mass fraction ratio of polypropylene particles to polyurethane particles is 2:1.

[0112] The buffer layer 12 is made of polyurethane foam and polyethylene foam as raw materials, which are stirred, mixed, plasticized and compacted in the cylinder by the placement of the extrusion screw of the extruder, and a certain shape of product is extruded from the die head, and the certain shape of product is subjected to strong extrusion and extension under the action of friction by a calender, forming a calendered product with uniform thickness, and the buffer layer 12 is formed by shearing processing, wherein the mass fraction ratio of polyurethane foam to polyethylene foam is 1:0.8-1.2.

[0113] The polishing layer 2 comprises a polishing bottom layer 21 and a polishing surface layer 22, the polishing surface layer 22 is adhered to the polishing bottom layer 21 by EVA hot melt adhesive, and the polishing bottom layer 21 is adhered to the buffer layer 12 by EVA hot melt adhesive, and the polishing surface layer 22 comprises the following raw materials in mass fraction: sub-micron cerium oxide 50-70 parts, zirconium oxide 2-5 parts, chromium oxide 5-10 parts, rare earth 10-15 parts, silicon dioxide 5-10 parts and the balance of cobalt.

[0114] The polishing base layer 21 is provided with a transverse polishing strip 212, and the transverse polishing strip 212 is integrally connected to the polishing base layer 21.

[0115] The polishing base layer 21 is made of thermoplastic polyurethane elastomer, and is stirred, mixed, plasticized, compressed, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and is subjected to shearing processing to form the polishing base layer 21.

[0116] The transverse polishing strip 212 is made of thermoplastic polyurethane elastomer and polypropylene, and is stirred, mixed, plasticized, compressed, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and is subjected to shearing processing to form the transverse polishing strip 212, wherein the thermoplastic polyurethane elastomer and the polypropylene include the following raw materials in mass fraction: 20 parts of thermoplastic polyurethane elastomer and 15 parts of polypropylene.

[0117] Compared with Example 1, the longitudinal polishing strip 211 structure is cancelled in Comparative Example 1, and the polishing pad is prepared by using the same preparation method as that of Example 1, and the preparation steps of the longitudinal polishing strip 211 are cancelled accordingly.

[0118] The polishing pads prepared in Examples 1-4 and Comparative Examples 1-2 are subjected to performance testing, and the polishing pad performance test results are shown in Table 1:

[0119] Table 1: Polishing pad performance test results

[0120]

[0121] From the above table, it can be seen that the polishing pads prepared in Examples 1-3 all have good porosity, modulus and wear resistance.

[0122] Among them, Example 2 compared with Example 1, its porosity is unchanged, modulus and wear resistance are all improved, which shows that increasing the mass fraction of polypropylene can improve the modulus and wear resistance of the polishing pad;

[0123] Among them, Example 3 compared with Example 1, its porosity is unchanged, modulus and wear resistance are all improved, which shows that increasing the mass fraction of thermoplastic polyurethane elastomer can improve the modulus and wear resistance of the polishing pad;

[0124] Among them, Comparative Example 1 compared with Example 1, its porosity, modulus and wear resistance are all reduced, because the transverse polishing strip 212 is not increased in Comparative Example 1, which leads to the reduction of the porosity, modulus and wear resistance of the polishing pad, which shows that the transverse polishing strip 212 can improve the porosity, modulus and wear resistance of the polishing pad;

[0125] The porosity, modulus and wear resistance of the comparative example two are all reduced compared with the example one, the porosity, modulus and wear resistance of the polishing pad are reduced due to the fact that the longitudinal polishing strip 211 is not added in the comparative example two, which shows that the longitudinal polishing strip 211 can improve the porosity, modulus and wear resistance of the polishing pad.

[0126] In conclusion, the polishing pad with high porosity and high modulus polishing layer and the preparation method thereof, the longitudinal polishing strip 211 and the transverse polishing strip 212 are prepared from the thermoplastic polyurethane elastomer and the polypropylene, and the longitudinal polishing strip 211 and the transverse polishing strip 212 are distributed in the polishing base layer 21 prepared from the thermoplastic polyurethane elastomer in a longitudinal and transverse staggered manner, the polishing pores 213 are formed between the longitudinal polishing strip 211 and the transverse polishing strip 212, and the polishing surface layer 22 is bonded to the surface of the polishing base layer 21, so that the polishing layer 2 prepared has the characteristics of high porosity and high modulus, the wear resistance and the storage modulus of the polishing pad can be improved, the polishing pad has high removal rate and good flatness, and the use effect of the polishing pad is improved.

[0127] It should be noted that the relational terms herein such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0128] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A polishing pad having a high porosity and high modulus polishing layer, comprising a base layer (1) and a polishing layer (2), characterized in that: A polishing layer (2) is provided on the base layer (1), and the polishing layer (2) is bonded to the base layer (1) by EVA hot melt adhesive, wherein the EVA hot melt adhesive comprises the following raw materials in parts by mass: 47-50 parts of EVA resin, 35-36 parts of tackifier, 8-12 parts of paraffin wax, 3-7 parts of filler, and 0.5-2 parts of antioxidant; The polishing layer (2) comprises a polishing bottom layer (21) and a polishing surface layer (22), wherein the polishing surface layer (22) is bonded to the polishing bottom layer (21) by EVA hot melt adhesive, and the polishing bottom layer (21) is bonded to the buffer layer (12) by EVA hot melt adhesive, and the polishing surface layer (22) comprises the following raw materials in parts by mass: 50-70 parts of submicron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide, and the balance of cobalt; The polishing bottom layer (21) is provided with longitudinal polishing strips (211) and transverse polishing strips (212), the longitudinal polishing strips (211) and transverse polishing strips (212) are connected, and the longitudinal polishing strips (211) and transverse polishing strips (212) are integrally connected to the polishing bottom layer (21), the longitudinal polishing strips (211) and transverse polishing strips (212) are distributed in a crisscross manner in the polishing bottom layer (21), and polishing pores (213) are formed between the longitudinal polishing strips (211) and transverse polishing strips (212).

2. The polishing pad having a high porosity and high modulus polishing layer according to claim 1, wherein: The base layer (1) comprises a base layer (11) and a buffer layer (12); the base layer (11) is bonded to the buffer layer (12) via EVA hot melt adhesive; and the buffer layer (12) is bonded to the polishing layer (2) via EVA hot melt adhesive.

3. The polishing pad having a high porosity and high modulus polishing layer according to claim 2, wherein: The base layer (11) is made of polypropylene pellets and polyurethane pellets, which are heated and melted by a screw extruder to form a melt. The two melts are extruded from the spinneret holes of the die head in opposite directions. The melts are blown by hot air flows on both sides of the spinneret holes, and are stretched into warp microfibers. The base layer (11) is formed by self-adhesion, wherein the mass ratio of the polypropylene pellets to the polyurethane pellets is 2:

1.

4. The polishing pad having a high porosity and high modulus polishing layer according to claim 3, wherein: The buffer layer (12) is made of polyurethane foam and polyethylene foam as raw materials, which are stirred, mixed, plasticized and compacted in a barrel by an extruder with the help of the placement of an extrusion screw, and a product of a certain shape is extruded from a die head. The extruded product of a certain shape is subjected to strong extrusion and extension under the action of friction in a calender to form a calendered product with uniform thickness. After shearing processing, the buffer layer (12) is formed, wherein the mass ratio of the polyurethane foam to the polyethylene foam is 1:0.8-1.

2.

5. The polishing pad having a high porosity and high modulus polishing layer according to claim 4, wherein: The polishing bottom layer (21) is made of thermoplastic polyurethane elastomer, which is stirred, mixed, plasticized, compacted, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and then sheared to form the polishing bottom layer (21).

6. The polishing pad having a high porosity and high modulus polishing layer according to claim 5, wherein: The longitudinal polishing strips (211) and the transverse polishing strips (212) are made of thermoplastic polyurethane elastomer and polypropylene as raw materials, and are stirred, mixed, plasticized, pressed, extruded and stretched by an extrusion molding machine to form a calendered product with uniform thickness, and are sheared to form the longitudinal polishing strips (211) and the transverse polishing strips (212), wherein the thermoplastic polyurethane elastomer and the polypropylene include the following raw materials in parts by mass: 20-36 parts of thermoplastic polyurethane elastomer and 15-32 parts of polypropylene.

7. A method for preparing a polishing pad having a high porosity and high modulus polishing layer according to claim 6, characterized in that: The steps include: S1. Preparation of substrate layer (1): Polypropylene pellets and polyurethane pellets with a mass ratio of 2:1 are added to a screw extruder, heated and melted by the screw extruder, and extruded into a melt. The two melts are extruded from the spinneret holes of the die head in opposite directions, and are blown by hot air currents on both sides of the spinneret holes. The melts are stretched into warp microfibers and form a base layer through self-adhesion (11); The polyurethane foam and polyethylene foam in a mass ratio of 1:0.8-1.2 are added to the extruder, stirred, mixed, plasticized and compacted in the barrel by the extruder with the help of the placement of the extrusion screw, and a product of a certain shape is extruded from the die head. The extruded product of a certain shape is strongly extruded and stretched under the action of friction in the calender to form a calendered product with uniform thickness, and a buffer layer (12) is formed after shearing processing; The prepared buffer layer (12) is bonded to the prepared base layer (11) by EVA hot melt adhesive, and after lamination, a base layer (1) is formed; S2. Preparation of polishing layer (2): The thermoplastic polyurethane elastomer is added to an extrusion molding machine, stirred, mixed, plasticized, compacted, extruded and stretched by the extrusion molding machine to form a calendered product with uniform thickness, and then subjected to shearing processing to form a polished bottom layer (21); A certain mass fraction of thermoplastic polyurethane elastomer and polypropylene are added to an extrusion molding machine, stirred, mixed, plasticized, compacted, extruded and stretched by the extrusion molding machine to form a calendered product with uniform thickness, and then subjected to shearing processing to form longitudinal polishing strips (211) and transverse polishing strips (212); Submicron cerium oxide, zirconium oxide, chromium oxide, rare earth, silicon dioxide and cobalt are added into a mixing grinder in proportion, mixed and ground thoroughly, and then molded to form a polished surface layer (22); A longitudinal polishing strip (211) and a transverse polishing strip (212) are machined into the polishing bottom layer (21), and polishing pores (213) are formed between the longitudinal polishing strip (211) and the transverse polishing strip (212), and the polishing surface layer (22) is bonded to the polishing bottom layer (21) by EVA hot melt adhesive to form a polishing layer (2); S3. Prepare polishing pad: The polishing layer (2) is bonded to the base layer (1) by EVA hot melt adhesive, and after lamination, a polishing pad is formed.

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